International Arbitration 2025

Last Updated August 21, 2025

Spain

Law and Practice

Authors



Cases & Lacambra is an international client-focused law firm strongly committed to offering the best and most comprehensive advice on business law. The firm, with offices in Europe and America, has a proven track record in complex transactions involving the financial sector, special situations, financial markets regulations, cross-border disputes, and transactions with specific tax-related considerations. The firm focuses on providing bespoke solutions to its clients, which include financial institutions, investment services companies, investment funds, insurance companies, energy sector companies, family offices, business conglomerates and high net worth individuals. The firm’s teams are not only highly qualified but also possess a wide range of experience across numerous sectors. Cases & Lacambra’s litigation and arbitration team works together with its clients, be they financial entities, multinational or national companies, and individuals, with the aim of avoiding potential disputes. If a dispute cannot be avoided, the firm represents clients in all kinds of judicial and arbitration proceedings.

In Spain, arbitration is the dispute resolution procedure of choice. Indeed, arbitral awards are automatically enforceable before ordinary courts (Article 517.2.2 of the Spanish Procedural Law, Act 1/2000, of 7 January 2000).

However, some domestic parties are still reluctant to use arbitration to resolve their disputes, although the prevalence of arbitration has increased because judicial proceedings are too slow in some parts of Spain.

In this regard, it is worth mentioning the reform of the Civil Procedure Act introduced by Organic Law 1/2025 of 2 January on measures to improve the efficiency of the Public Justice Service, which introduces the requirement to resort to an alternative means of dispute resolution prior to filing a lawsuit. This requirement, applicable to ordinary jurisdiction proceedings, has been in force since 3 April 2025.

This circumstance may lead some parties to opt for arbitration instead of ordinary jurisdiction. However, given that this requirement has only been in force for a few months, we cannot predict the effects that this reform will have.

With respect to international arbitration proceedings, Article 3 of the Spanish Arbitration Act 60/2003 of 23 December 2003 (SAA) states that arbitration proceedings shall be considered international when any of the following circumstances apply:

  • At the time of the conclusion of the arbitration agreement, the parties have their domiciles in different countries.
  • The place of arbitration, determined in or pursuant to the arbitration agreement, the place of performance of a substantial part of the obligations in dispute or the place with which the dispute is most closely connected, is outside the state in which the parties have their domiciles.
  • The legal relationship in dispute is connected to international trade interests.

Therefore, under Spanish law, arbitration proceedings will be considered international only in those cases.

Between 2021 and 2024, international arbitration has increased exponentially in fields that require higher levels of expertise.

This is the case for the construction and energy industries, in which it is quite common for the contracting parties to agree to submit their disputes to international arbitration due to the specific expertise required for the resolution of those kinds of proceedings.

In Spain, the most frequently used international arbitration court is the Court of Arbitration of the International Chamber of Commerce (ICC).

Moreover, until 2020 there were four arbitral institutions in Spain used for international arbitration:

  • the Madrid Court of Arbitration (Corte de Arbitraje de Madrid);
  • the Civil and Commercial Court of Arbitration (Corte Civil y Mercantil de Arbitraje – CIMA);
  • the Spanish Court of Arbitration (Corte Española de Arbitraje); and
  • the Arbitration Court of Barcelona (Tribunal Arbitral de Barcelona).

No arbitration institution has been created in the last 12 months. However, on 1 January 2020, the Madrid International Arbitration Center (Centro Internacional de Arbitraje de Madrid – CIAM) began its activity. CIAM was created following an agreement reached between the Madrid Court of Arbitration, CIMA and the Spanish Court of Arbitration to promote international arbitration in Spain.

In Spain, there are no specific national courts to hear disputes related to international arbitrations and/or domestic arbitrations.

However, there are some national courts that have specific powers regarding international arbitration.

For instance, the courts of first instance (Juzgados de Primera Instancia) are entitled to recognise and enforce international arbitration awards per Article 8.6 of the SAA, while the high courts of justice (Tribunales Superiores de Justicia) have jurisdiction to hear appeals for the annulment of awards.

In Spain, the governing law on arbitration is the SAA, which includes both domestic and international arbitration.

This law draws heavily on the United Nations Commission on International Trade Law of 21 June 1985 (the UNCITRAL Model Law). Key similarities include the requirements for a valid agreement to submit to arbitration and the adoption of interim measures in arbitration proceedings.

However, it should be noted that, in addition to the SAA, Spanish law also incorporates the provisions relating to international arbitration established in treaties ratified by Spain or contained in national laws with special provisions on arbitration.

The main differences between the SAA and the UNCITRAL Model Law include the following.

  • In accordance with Section 9.6 of the SAA, in international arbitrations, the arbitration agreement will be valid and the dispute shall be arbitrable if it meets the requirements stated by the law chosen by the parties to govern the arbitration agreement, by the law governing the merits of the case or by Spanish law.
  • In accordance with Article 15 of the SAA, unless otherwise agreed by the parties, in arbitrations that are not to be decided in equity, when the arbitration is to be decided by a sole arbitrator, the arbitrator shall be an attorney.

The Spanish arbitration legislation has not been modified in recent years.

According to Article 9.1 of the SAA, to be valid under Spanish law, an arbitration agreement has to express the parties’ willingness to submit to arbitration all or some disputes that may arise from their legal relationship. In this sense, the Spanish law follows Article 7 of the UNCITRAL.

Therefore, the key aspect to be considered in an arbitration agreement is to clearly state the intention of the parties to submit their dispute to arbitration.

In addition, an arbitration agreement must be made in writing and signed by both parties or exchanged in communications between the parties which provide a record of the agreement (Article 9.3, SAA).

On the other hand, in international arbitrations, the SAA expressly provides that the arbitration agreement will be valid if it meets the requirements stated by the law chosen by the parties to govern the arbitration agreement, by the law governing the merits of the case or by Spanish law (Article 9.6, SAA).

Under Spanish law, the matters that cannot be submitted to arbitration are matters excluded from the free disposition of the parties. These would be considered non-arbitrable matters (Article 2.1, SAA). Moreover, Article 1.4 of the SAA excludes labour disputes from the scope of the law and, in addition, there are matters excluded from arbitration for reasons of public order, such as disputes related to personal capacity or filiation.

Regarding the determination of the law applicable to the arbitration agreement, the main rule is the freedom of choice of the parties. In international arbitration, if there is no choice, Article 9.6 of the SAA provides that the arbitration agreement will be valid if it meets the requirements stated by the law governing the merits of the case or by Spanish law.

The Spanish courts follow this rule and do not intervene in those cases in which they lack jurisdiction unless expressly provided for by the SAA, as set forth in Article 7 of the SAA.

In this regard, in cases where there is an arbitration agreement, the national courts will refrain from hearing the dispute and will accept the decision of the parties to submit to arbitration.

Likewise, if there is an arbitration agreement between the parties, the opposing party may also allege the lack of jurisdiction of the court through a motion for lack of jurisdiction.

If the contract in which the submission to arbitration clause is contained is invalid, the arbitration clause will not be affected by the invalidity. The arbitration clause is considered a separate legal stipulation from the main contract regardless of whether it is set as a clause within the contract itself or as a separate contract.

In this sense, the principle of competence-competence is expressly recognised in Article 22 of the SAA. This principle states that arbitrators are empowered to decide on their own jurisdiction, including any plea related to the existence or validity of the arbitration agreement, or any other pleas, the acceptance of which would prevent the consideration of the merits of the case.

According to Article 15 of the SAA, in arbitrations of law, the only limit set to the parties’ autonomy is that at least one of the arbitrators must be an attorney. On the other hand, there is no such limitation in equity arbitrations, and there is no requirement that an arbitrator be an attorney, not even in cases in which it is solved by a sole arbitrator.

In addition, it should be noted that the arbitrators cannot be legal entities, and there is no maximum limit to the number of arbitrators as long as they are odd-numbered.

The parties are free to agree on a procedure to appoint the arbitrator(s); however, if the arbitrator(s) cannot be appointed under that procedure, any party may apply to the competent court to appoint the arbitrators or, as appropriate, to adopt the necessary measures.

For those cases, Article 15 of the SAA establishes the following procedure to appoint the arbitrator(s):

  • In an arbitration with a sole arbitrator, they will be appointed by the competent judicial court at the request of any of the parties.
  • In an arbitration with three arbitrators, the parties will appoint one arbitrator each, and these two arbitrators will appoint the third arbitrator, who will be the chairperson of the arbitral tribunal. If a party fails to appoint the arbitrator within 30 days of the latest acceptance, the appointment will be made by the competent judicial court at the request of any of the parties.
  • Where more than one claimant or respondent is involved, the claimants will appoint one arbitrator and the respondents will appoint another. If claimants or respondents cannot agree on the appointment, all arbitrators will be appointed by the competent judicial court at the request of any of the parties.

If the arbitration is administered by an arbitration institution, the latter will apply its own rules for appointing arbitrators.

As stated in Article 8.1 of the SAA, the Spanish courts will intervene in the selection of the arbitrators when it has not been possible to appoint the arbitrator(s) by the method stipulated by the parties, in the following cases:

  • when the arbitration should be overseen by a single arbitrator and the arbitrator could not be determined in accordance with the stipulations agreed by the parties;
  • when the arbitration should be overseen by three arbitrators but one of the parties has not selected the corresponding arbitrator within a period of 30 days; or
  • when there are several plaintiffs or defendants and they do not reach an agreement on appointing an arbitrator.

The SAA is flexible in relation to the procedure for challenging arbitrators. It allows the parties to agree on the challenge procedure they deem most appropriate.

However, in the absence of an agreement, the party challenging an arbitrator shall state the reasons for the challenge within 15 days of becoming aware of the acceptance or of any circumstances that may give rise to justifiable doubts as to the arbitrator’s impartiality or independence.

Unless the challenged arbitrator withdraws from their position or the other party accepts the challenge, it shall be for the arbitrators to decide on the challenge.

The grounds on which the arbitrators may be challenged must be based on whether there are circumstances giving rise to justifiable doubts as to their impartiality or independence, or as to whether they possess the qualifications agreed upon by the parties.

The arbitrator must be impartial and independent. To avoid being challenged, they must remain independent and impartial throughout the arbitration (Article 17.1, SAA).

Despite the fact that no definitions of independence and impartiality are established in Spanish law, they usually consist of maintaining the absence of any personal, professional or commercial relationship with the parties, and should an arbitrator have any impediment that prevents them from meeting these requirements, they must disclose this information at the time of their appointment and without delay.

In this regard, we must point out that the Spanish Arbitration Club approved the Code of Best Practice, which includes recommendations regarding the arbitrators’ standards of independence.

In accordance with Article 22 of the SAA, the arbitrators appointed in an arbitration procedure are fully empowered to decide on their own jurisdiction (the competence-competence principle). This includes the power to decide if the arbitration agreement exists or if it is valid.

A court may address issues of jurisdiction of an arbitral tribunal if a party files a claim with the court despite the fact that the parties have agreed on an arbitration clause. In this case, the defendant could file a motion for lack of jurisdiction invoking the existence of the arbitration agreement and could request the court to refrain from ruling on the matter. All of this is settled in accordance with Article 11.1 of the SAA and Article 63 of the Spanish Civil Procedure Law.

If the existence of the arbitration agreement can be clearly proved, the Spanish courts will refrain from intervening in the procedure.

The SAA does not establish the option for Spanish courts to review negative decisions on jurisdiction by arbitral tribunals, although jurisdiction may be reviewed by means of an action for annulment of the award (Article 41, SAA).

The parties can only challenge the jurisdiction of an arbitral tribunal before the courts when an award has been issued (interim or final), since Article 22 of the SAA grants exclusive jurisdiction to the arbitrators to decide on their own jurisdiction.

Therefore, the decision of the arbitrators on their own jurisdiction can only be challenged through the exercise of an action for annulment of the award, without prejudice to the fact that the parties could allege before the arbitral tribunal its lack of jurisdiction in their first writ of allegations.

The Spanish courts will analyse the specific jurisdiction of the arbitral tribunal through a deferential review.

In the event that a party files a claim when it should have initiated arbitration proceedings due to the existence of an arbitration agreement, the court should act in accordance with the arbitration agreement unless it considers it to be invalid.

It should also be noted that the parties may modify the submission made to arbitration by tacitly submitting the dispute to the courts. Thus, if a claim has been filed with a court despite the fact that the parties have agreed on an arbitration clause and the opposing party replies to the claim without objecting to the jurisdiction of the tribunal within ten days, it will be understood that the parties have agreed to submit their dispute to the jurisdiction of that court.

Spanish law does not recognise the capacity of arbitral tribunals to uphold jurisdiction over persons or entities that are not parties to the arbitration agreement.

However, there are certain cases in which it has been accepted that arbitration agreements may affect non-signatory parties if they have a close and strong relationship with the signatories or play a relevant role in the execution of the contract submitted to arbitration.

Article 23 of the SAA establishes that arbitrators may, at the request of a party, adopt the precautionary measures that they deem necessary in relation to the object of the proceedings. In such cases, arbitrators may require the claimant to furnish sufficient security.

The SAA does not detail any specific interim measures and, therefore, arbitrators commonly apply by analogy some of the measures listed in Article 727 of the Spanish Procedural Law (Act 1/2000, of 7 January 2000), such as preventive seizure of goods, judicial intervention or administration of productive goods, goods depository, etc.

The competence to adopt precautionary measures in the framework of arbitration procedures vests in the arbitrators themselves. However, to achieve effective compliance, the collaboration of the courts is often necessary.

Moreover, it is worth mentioning that the national courts can grant interim measures in aid of international arbitration in accordance with Article 722 (first paragraph) of the Spanish Procedural Law (Act 1/200, of 7 January 2000), which regulates interim measures in arbitration proceedings and foreign litigation. This provision determines that whoever can prove to be a party to an arbitration agreement may seek injunctions from the court prior to or during the arbitration proceedings.

According to Article 722 of the Spanish Procedural Law, whoever can prove to be a party to any judicial or arbitration proceedings being conducted in a foreign country can request interim measures in Spain, except in the cases where the main matter at issue should lie solely within the competence of Spanish courts.

Although the SAA does not regulate the use of emergency arbitrators, the Madrid International Arbitration Center’s Arbitration Rules include a specific procedure for the request of urgent interim measures by any of the parties.

In this sense, the decision of the emergency arbitrators will be binding for the parties and will cease to be binding if the court terminates the request for emergency arbitration or if the request for arbitration has not been filed within the established time limit, among other reasons.

In this regard, the arbitrators of the main proceedings will have the ability to modify, suspend or revoke the decision of the emergency arbitrator, provided that one of the parties requests it.

When interim relief is requested in an arbitration procedure, the arbitrators can, in accordance with Article 23 of the SAA, require the requesting party to pay a bond to ensure that they can repay the damages that the requested measure could potentially cause to the other party.

In Spain, the principle of party autonomy, regulated in Article 25.1 of the SAA, governs the arbitration procedure.

Therefore, the only mandatory rule that governs the arbitration procedure is respect for due process rights (ie, the right to be heard and the equal treatment and contradiction of the parties).

As mentioned in 7.1. Governing Rules, the principle of party autonomy will govern the arbitration procedure, respecting the principles of due process and equal treatment in all cases.

Spanish national law does not contain a list of arbitrators’ duties and powers. However, they include the following.

  • Duties:
    1. they must act in a fair and impartial manner, treating both parties equally;
    2. their performance has to fall within the established legal or contractual framework; and
    3. they must keep the procedure confidential.
  • Powers:
    1. the power to decide on their own competence; and
    2. the power to adopt interim reliefs.

It should be pointed out that the Spanish Arbitration Club has approved the Code of Best Practice, which includes recommendations regarding the arbitrators’ duties.

The SAA does not include legal provisions that provide for particular qualifications or other requirements for legal representatives, beyond requiring that the representative have sufficient powers to act as such.

As regards the collection and submission of evidence at the pleading stage and at the hearing in the Spanish jurisdiction, it should be noted that the parties are free to choose the applicable rules of evidence, subject to the requirements adopted by the arbitration institution where the arbitration takes place.

Thus, as for the existence of specific rules applicable to the different types of evidence, the arbitrator may order the disclosure of documents and the appearance of witnesses. They may even request the assistance of the competent court in the submission of evidence, in accordance with Article 33 of the SAA.

In this regard, with respect to the possibility of one party disclosing documents to the other party or the arbitrator, it should be noted that the parties may fix the rules and scope of disclosure by mutual agreement, which must be approved by the arbitrator.

According to the SAA, the parties and the arbitrator will have full freedom and flexibility in the evidence phase. Thus, as long as the principles of equality and contradiction are complied with, there is no difference between international arbitration and national proceedings.

In this regard, if the arbitration is administered by an arbitral institution, the rules of evidence could be those established by that particular institution.

On the other hand, if the arbitration is an ad hoc arbitration and the parties have not agreed on the rules of evidence, the arbitrators shall determine how it is to be regulated, provided that the principle of equal treatment is granted.

According to Article 33 of the SAA, the assistance of the courts in the collection or submission of evidence may be requested whenever necessary.

It is the first instance court of the place of arbitration or of the place where the assistance is requested that will assist the parties or the arbitrators in the taking of evidence. Such assistance may consist of the collection or submission of evidence by the court itself or the adoption of specific measures to enable the collection or submission of certain evidence.

Article 24.2 of the SAA expressly establishes that the arbitrators, the parties, and the arbitral institutions must respect the confidentiality of the information and documentation provided for in the arbitration proceedings.

The principle of confidentiality affects both the information and documentation related to the merits of the case, as well as the documentation and evidence related to the arbitration proceedings.

The legal requirements for an arbitral award to be valid and enforceable in Spain are set forth in Article 37 of the SAA. They can be summarised as follows:

  • The time limit for rendering the award is six months from the filing of the statement of defence or from the expiration of the time limit for filing it, unless otherwise agreed.
  • The award must be made in writing and signed by the arbitrators.
  • The award must include a statement of the reasons on which the decision is based, unless it is rendered by termination by mutual agreement of the parties.
  • The award must contain a specific decision on the costs of the arbitration.
  • The award must be expressly notified to the parties, in the manner and within the period agreed by the parties or, failing this, by delivery of a signed copy of the award to each party.

The six-month period for delivery of the award, unless otherwise agreed, may be extended in a duly justified manner by the arbitrators for a period not exceeding two months.

As to the types of remedies that an arbitral tribunal may award, arbitrators can award both declaratory relief and monetary compensation.

At the same time, arbitrators have the possibility of ordering the specific performance of a contract by one of the parties or the pursuit of a certain action.

However, as regards the existing limits on such remedies, it is necessary to specify that punitive damages do not exist in Spain and, consequently, it could be understood that they are contrary to public policy.

Pursuant to Article 37.6 of the SAA, the arbitrators’ award on the costs of the arbitration shall include the following:

  • the fees and expenses of the arbitrator and, if applicable, the fees and expenses of the defence and of the representatives of the parties;
  • the cost of the services rendered by the arbitration institution; and
  • all other expenses incurred within the arbitration proceedings.

Also, the payment of legal interest concerning the principal sum awarded is generally imposed.

Unless otherwise agreed by the parties, the arbitrators shall decide on the distribution of the costs generated by the arbitration proceedings. Thus, the arbitrators can decide whether to distribute the costs depending on the costs incurred by each party, or whether one party should compensate the other for the costs incurred.

According to Article 41 of the SAA, an award may be set aside if any of the following circumstances is proved:

  • The arbitration agreement does not exist or is invalid.
  • It has not been possible to give proper notice of the appointment of an arbitrator or of the arbitral proceedings, or a party has not been able to assert its rights.
  • The arbitrators have ruled on matters not submitted to their decision.
  • The appointment of the arbitrators or the arbitration proceedings have not been in accordance with the agreement of the parties, unless such agreement would be contrary to a mandatory rule of the SAA, or, in the absence of such agreement, they have not been in accordance with the SA.
  • The arbitrators have ruled on matters not subject to arbitration.
  • The award is contrary to public policy.

The party requesting the award to be declared null and void must file a claim with the high court of justice of the Autonomous Community in which the award has been rendered.

Generally, the application for annulment of the award may be filed within a maximum period of two months from the date of receipt of the award by the applicant party. However, when one party (or both) applies for rectification, clarification or supplementation of the award, the time limit will begin from the date of receipt of the decision on the application by the applicant party or from the date of expiration of the time limit for deciding on the application.

The annulment action will be substantiated through the channels of the verbal proceedings, but with the following particularities:

  • The claim must contain the documents supporting the claim, the arbitration agreement and the award, and, if applicable, it shall contain a proposal for the measure that is of interest to the plaintiff.
  • The time limit for replying to the appeal by the opposing party shall be 20 days and must contain the means of proof for the measure that is of interest to them.

The SAA does not regulate the possibility of excluding or expanding the scope of appeal of the awards since, in the Spanish legal system, there is no second instance in arbitration matters. Instead, there is the possibility of filing an action for annulment on the grounds set out in the law, which in no case affects the merits of the case.

Thus, the voluntary submission of the parties to arbitration has the consequence that the possibilities for appealing the decision arising from the proceedings are limited.

In this regard, it should be noted that the exclusion by the parties of the action for annulment of the award is not allowed under Spanish law.

The standard of judicial review is deferential, since the courts cannot review the merits of the dispute resolved by the arbitrator.

According to Article 41 of the SAA, an award may be set aside if any of the following circumstances is proved:

  • The arbitration agreement does not exist or is invalid.
  • It has not been possible to give proper notice of the appointment of an arbitrator or of the arbitral proceedings, or a party has not been able to assert its rights.
  • The arbitrators have ruled on matters not submitted for their decision.
  • The appointment of the arbitrators or the arbitration proceedings have not been in accordance with the agreement of the parties, unless such agreement would be contrary to a mandatory rule of the SAA, or, in the absence of such an agreement, they have not been in accordance with the SAA.
  • The arbitrators have ruled on matters not subject to arbitration.
  • The award is contrary to public policy.

As can be seen, the law does not recognise the possibility of applying for the annulment of an award on the grounds that the rules applicable to the merits of the case have been violated.

In July 1977, Spain enforced the Convention on the Recognition and Enforcement of Arbitral Awards, as adopted in New York in June 1958, which is the instrument that generally governs the enforcement of international awards in Spain.

This is established in Article 46 of the SAA. However, it also mentioned that the aforementioned New York Convention will be applicable in the absence of international conventions that are more favourable.

In Spain, the procedure and rules for the enforcement of an award depend on whether the award to be enforced is national or international.

If the award is national, the party seeking to enforce the award simply has to apply for enforcement before the court of first instance of the place in which the award was rendered.

On the other hand, if the award is international, the general rule is that a party must apply for its recognition before the court of justice of the domicile of the party against whom the award is to be enforced, or in the place where the award should produce its effects.

Once it is recognised, enforcement may be sought before the court of first instance of the domicile of the person against whom the award is to be enforced, or where it should produce its effects.

The international relevance of annulment decisions made by the courts in the country in which arbitration took place is controversial. In general, if an award is annulled in the state of origin, it will not be subject to recognition in another state, since, if it is not valid in its state of origin, it cannot be valid in any other jurisdiction.

In any case, denying a foreign award because it has been annulled by a foreign court decision means giving effect, indirectly, to the award in Spain.

In conclusion, there is a wide margin of manoeuvre for Spanish courts not to deny the exequatur of foreign arbitral awards that have been annulled on grounds contrary to Spanish public policy.

On the other hand, if the appeal for annulment of the foreign award is still pending, the Spanish exequatur court may postpone the decision on the enforcement of the award.

Regarding the possibility for a state or state entity to successfully raise a defence of state or sovereign immunity in the enforcement stage, Article 2.2 of the SAA prevents the possibility of a state opposing the prerogatives of its own law to breach the obligations contained in an arbitration agreement.

Therefore, in 2015, Spain passed Act 16/2015, on State Immunity, which covers the content of the UN Convention on State Immunity (UNCSI) of 2004. In this regard, according to Article 16 of the UNCSI, there is an exception to jurisdictional immunity when there is an arbitration agreement relating to a commercial transaction between the state and a private individual from a different state.

Thus, Article 17 of the UNCSI provides for the immunity of the state from enforcement measures, as it allows enforcement proceedings against assets located in Spain and used for purposes other than official non-commercial ones. In turn, enforcement will be possible when there is a tacit or explicit consent of the state by means of an international agreement, a written contract or a declaration within a judicial proceeding.

The case law of the Spanish courts in relation to the exequatur of foreign awards respects the autonomy of the will of the parties to submit their dispute to arbitration and, consequently, interprets the principle of public policy in a restrictive manner.

Occasionally, there are some decisions that cause some controversy as to the scope and extent of the concept of public policy, but generally the exceptionality of its nature is recognised.

In Spain, the only dedicated regulation pertaining to class-action arbitration is the Royal Decree 231/2008, of 15 February 2008, which regulates the consumer arbitration system.

In general, class action in arbitration is neither ruled out nor adequately covered by current legislation. However, due to the specific characteristics of class actions, it is difficult to carry out an arbitration procedure without specific regulation of these procedures.

In this sense, in class actions brought before the ordinary courts, Spanish law requires, for example, the publicity of the actions in order for the plaintiffs to join the proceeding and request their individual compensation.

Regarding class actions before courts, the bill on representative actions for the protection of the collective interests of consumers is pending approval by the Spanish Parliament. This bill transposes the Directive (EU) 2020/1828 of the European Parliament and of the Council of 25 November 2020 on representative actions for the protection of the collective interests of consumers and repealing Directive 2009/22/EC.

The Arbitration Law does not include ethical codes binding arbitrators and lawyers. Thus, the only requirements are independence and impartiality. However, it is true that arbitrators and lawyers admitted to the bar are obliged to comply with the professional code and the ethical rules applicable to lawyers.

Spanish practitioners are also aware of the guidelines accepted by the International Bar Association and the Spanish Arbitration Club, which include ethical rules.

Arbitration and national laws do not regulate third-party funding. However, there is also no regulation applicable to arbitration or civil procedure that prevents third-party funding.

Regarding class actions filed before courts, the aforementioned Directive (EU) 2020/1828 regulates third-party funding and the draft of the Spanish Law on this matter also foresees third-party funding.

The use of third-party funders in arbitration is commonly accepted. However, the lack of regulation causes some doubts, for example, regarding the costs to be imposed in the award.

The SAA does not regulate the possibility for an arbitral tribunal or court in Spain to consolidate several separate arbitration proceedings.

However, the fact that this aspect is not regulated does not mean that it is prohibited, since it will depend on the procedural rules agreed upon by the parties, in accordance with Article 26 of the SAA.

In this sense, the Madrid International Arbitration Centre provides for the consolidation of several arbitration proceedings.

In conclusion, the agreement of the parties and the internal regulations of the arbitration institution in which the arbitration is being administered must be followed.

It must be taken into account that the scope of the award must be limited to the parties who entered into the arbitration agreement and who participated in the arbitration process. An award does not have effects on third parties who were not able to exercise their right of defence within the arbitration process itself.

When the effects of the award are intended to be extended to third parties who did not participate in the arbitration, they must challenge the award through constitutional channels, as long as there is a direct impact and they affect their constitutional rights.

However, there are certain cases in which it has been admitted that arbitration agreements may affect non-signatories if they have a close and strong relationship with the signatories or play a relevant role in the execution of the contract submitted to arbitration.

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Trends and Developments


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Broseta Abogados was founded in 1975. It is a full-service business law firm with a strong reputation in the Spanish and Iberian legal markets. The firm advises domestic and international corporations, financial institutions, investment funds, public sector entities and family-owned businesses on complex legal and regulatory matters. Broseta operates through offices in Madrid, Valencia, Barcelona, Lisbon and Zurich, providing clients with extensive coverage across key business and financial centres. The firm brings together more than 300 professionals, including lawyers and multidisciplinary specialists, organised into highly specialised practice groups that deliver expert advice across all areas of business law. The firm is particularly recognised for its client-focused approach, combining technical excellence with a deep understanding of industry sectors and commercial objectives. Through its membership in the Ibero-American Legal Network, Broseta offers clients coordinated legal support across multiple jurisdictions, strengthening its ability to assist businesses with cross-border transactions, international expansion projects and multi-jurisdictional matters throughout Europe and Latin America.

Recent Developments: Procedural Innovation, Artificial Intelligence and Judicial Review

Overview

These are good times for arbitration in Spain. The figures show arbitration is gradually consolidating itself as a real and effective alternative to litigating before Spanish courts, whose proceedings in 2025 have reached an average duration of close to 30 months between first and second instance. The catalyst in 2025 has been the entry into force of Organic Law 1/2025, of 2 January, on measures to improve the efficiency of the public justice service. This has brought about a profound transformation of civil and commercial proceedings, introducing as a procedural requirement the obligation to attempt an out-of-court dispute resolution mechanism (ADR) beforehand and a judicial reorganisation with the introduction of the so-called courts of first instance. The initial uncertainty regarding how these two new elements would be implemented, together with the lack of unified interpretative criteria for the new regulation, may have indirectly encouraged recourse to arbitration as an effective method of dispute resolution.

This, combined with the excellent work carried out by the various arbitration institutions in Spain and an increasingly consolidated and robust body of case law from the Constitutional Court on the annulment of arbitral awards, has made 2025 a particularly fruitful year that paves the way for future developments.

At the domestic level, in 2024 the Madrid Court of Arbitration administered 98 arbitrations, with disputes totalling EUR642 million and averaging EUR7.3 million per case. In 2025, activity increased to 110 proceedings, representing a 12% rise compared to the previous year, and EUR755 million in dispute (an 18% increase), with an average amount of EUR7.9 million, pointing to higher-value and more complex disputes. Meanwhile, the Spanish Arbitration Court (CEA) administered 28 proceedings in 2025, with disputes totalling EUR131 million and averaging EUR4.6 million per case. Insurance, corporate, and energy were the main sectors in 2025. The average duration of its cases is 11 months.

In international arbitration, the Centro Internacional e Iberoamericano de Arbitraje (CIIAM) closed 2024 with 18 cases and nearly EUR128 million in dispute. The average amount exceeded EUR7 million. Since its creation in 2020, it has accumulated 53 cases and EUR280 million. The sectors with the highest volume of cases include corporate (33%), food and pharmaceutical (16.67%) and energy (16.67%). The average duration of cases administered by CIIAM has improved, standing at under one year (11 months) in its expedited procedure. Within the ICC, Spain ranked among the top ten jurisdictions designated as a seat in 2025, alongside France, the United Kingdom, the United States, Switzerland, Singapore, Brazil, Germany, Mexico and the United Arab Emirates.

The hyper-expedited procedure is introduced in Spanish arbitration institutions

Speed is one of the main advantages offered by arbitration, and Spanish arbitration institutions are adapting their rules to enable dispute resolution in less time and with greater efficiency.

Thus, following the path already established by CIIAM in 2023, the Madrid Court of Arbitration introduced a new set of rules on 1 January 2025 that includes significant developments, such as the simplification of the procedural phase. This grants greater flexibility to the parties and arbitrators to tailor the process to their needs and aims to improve the user experience by aligning the new rules with those of CIIAM. Provisions have been introduced regarding third-party intervention and consolidation of proceedings; changes have been made to the procedures for the appointment, confirmation and designation of arbitrators to streamline them; a hyper-expedited procedure has been incorporated, allowing for an award to be rendered within three months from the filing of the claim; and the optional challenge procedure for awards has been revised. These changes likely explain why the average duration of cases administered by this court has decreased from 11.5 months in 2024 to 7.2 months in 2025.

The Spanish Arbitration Court has also introduced new rules, which as of 1 January 2026 include, as a novelty, a hyper-expedited procedure as well as the optional challenge of awards. In this way, its rules are also harmonised with those of CIIAM, reducing operational complexities and ensuring a more coherent and accessible regulatory framework, thereby providing greater legal certainty for arbitration users.

The hyper-expedited procedure coexists alongside ordinary and expedited procedures within the rules. It is an accelerated process designed for resolving non-complex disputes or those requiring an immediate decision, and it is always conducted before a sole arbitrator (appointed by the parties within seven days of the response to the request for arbitration or, failing that, by the institution within a further seven days). It applies only with the express agreement of the parties (opt-in), and its main feature is the parallel conduct of the arbitrator appointment phase and the written phase of the arbitration.

The time limit for filing the claim begins automatically from the institution’s decision to administer the arbitration under the hyper-expedited procedure, and from that point, the deadlines for the statement of defence, counterclaim, and reply to the counterclaim begin to run. There is no first procedural order and, as a general rule, no evidentiary hearings are held, nor is there a closing submissions phase, without prejudice to the arbitrator’s discretion to order them after hearing the parties.

Time limits are also shortened; the claim must be filed within 15 days from the institution’s decision to proceed under the hyper-expedited procedure. The defence and, where applicable, the counterclaim must be submitted within a further 15 days, and the reply to the counterclaim within an additional 15 days.

The award must be rendered within three months from the filing of the claim. This, together with the parallel appointment phase, may result in an award being issued in just over four months from the request for arbitration.

Artificial intelligence in arbitration

Artificial intelligence (AI) has expanded rapidly in recent years across all areas of life, and arbitration is no exception. While there is consensus within the arbitration community that it can be a highly useful tool in managing arbitral proceedings, there is particular concern about the potential erosion of the legitimacy and impartiality of arbitral decisions, as well as confidentiality – an essential and defining feature of arbitration – among other issues.

AI is currently used in arbitration for legal research and concept searches; editing and proofreading of evidence; translation and interpretation; transcription; generation of briefing notes, diagrams and text summaries; drafting of communications and submissions; document production; document management; review, analysis and presentation of evidence; drafting of examination and cross-examination questions; arbitrator selection; and case valuation analysis.

Aware of the new challenges posed by AI, CIIAM published its report on principles and recommendations for the use of artificial intelligence systems in arbitral proceedings in 2025. Prepared by its Working Group on Digital Economy and Intellectual Property, it lays the groundwork for a future AI Usage Guide. This report focuses exclusively on the use of AI by the arbitral tribunal in arbitral proceedings and establishes fundamental principles such as respect for party autonomy, protection of confidentiality, procedural integrity, the arbitrator’s responsibility and control over the decision, as well as traceability and regulatory compliance.

The guide generally permits the use of AI and notes that there is currently no Spanish or European Union regulation prohibiting its use in arbitration. It therefore provides that the parties may agree in the arbitration clause – or subsequently, the arbitral tribunal, with the parties’ agreement, may determine at the first procedural order – the possibility, scope, and conditions for the use of AI systems in the arbitral proceedings.

One of the central points of the guide reminds the arbitrator that their role is exercised intuitu personae and that they remain the sole decision-maker. The use of AI systems neither eliminates nor reduces their responsibility, nor does it alter their duties as arbitrator. Even when assisted by AI systems, the arbitrator remains responsible for personally and independently analysing the facts, evidence, and law, as well as for the reasoning behind the decision. The arbitrator must therefore ensure that the use of AI systems for certain tasks or activities does not undermine their ability to independently assess the facts, evidence and applicable law. In short, the arbitral tribunal may not rely on the use of AI to exempt or limit its responsibility.

In addition to safeguarding the integrity of the decision, the arbitrator must also ensure the integrity of the proceedings. This means ensuring that AI does not artificially generate data, facts, or content that are false, incorrect, or unrelated to the proceedings. The arbitral tribunal must at all times be able to review and verify that the system does not alter, modify, or incorrectly analyse the facts, evidence, or applicable law.

The guide assigns responsibility to the arbitral tribunal for the use of AI, encouraging it to verify that the system used complies with applicable regulations, particularly personal data protection guidelines, and to ensure that the deployment and use of AI systems for the purposes of the arbitral proceedings comply with all applicable rules. Likewise, it must ensure that AI does not jeopardise or compromise the confidentiality of the proceedings at any stage, including submitted documentation and deliberations, both during the proceedings and at any later time.

Furthermore, the arbitral tribunal must inform itself of the possible uses and functionalities offered by the provider, as well as any limitations set out in the terms and conditions. The tribunal must also understand the system’s potential limitations and risks, such as hallucinations, inconsistencies and biases in outputs; and acquire adequate competence for the intended use of the system within the context of the arbitral proceedings.

Any AI system used in arbitral proceedings must technically allow for traceability of its processes and actions through automatic logging of its operations throughout the system’s lifecycle, in a manner appropriate to its intended purpose.

It remains to be seen how CIIAM will implement these principles in its rules. However, it has already taken steps to establish the minimum standards necessary to ensure that AI is used effectively and in a manner that respects the parties’ rights. In doing so, CIIAM demonstrates that it is committed to the development of present and future arbitration.

Case law: arbitration and mandatory European Union rules

In the case law landscape, a judgment of the Constitutional Court (TC) had a significant impact on the arbitration community at the beginning of 2025. This is Judgment No. 146/2024 of 2 December (Official State Gazette No. 5 of 6 January 2025), which upheld the claimant’s appeal and annulled Judgment No. 66/2021 issued by the High Court of Justice (TSJM) of Madrid on 22 October 2021. That earlier judgment had set aside an arbitral award at the request of Maxi Mobility Spain SLU (Cabify) against Auro New Transport Concept SL (Auro).

The underlying issue concerns the limits of judicial review of arbitral awards when mandatory rules of European Union law are involved – rules which the Court of Justice of the European Union (CJEU) itself characterises as forming part of public policy, in this case those governing competition law (Article 101 of the Treaty on the Functioning of the European Union). The debate centres on whether the court should carry out only an external review of the award, as proposed by the Constitutional Court in this judgment, or whether it must instead verify full compliance with mandatory EU rules.

Judgment No. 146/2024 states that the court hearing an action to set aside an award may verify that the award contains reasoning, but may not assess the adequacy, sufficiency, or legal correctness of that reasoning. It must confine itself to a “purely formal or external review” of the award’s reasoning. The court may only verify that the reasoning “is not unreasonable or arbitrary, nor based on non-existent premises, nor follows a line of argument containing logical flaws of such magnitude that the conclusions reached cannot be considered grounded in any of the reasons put forward.”

Accordingly, in the view of the Constitutional Court, when reviewing an arbitral award, courts may not examine the merits of the dispute submitted to arbitration or substitute the arbitrator’s decision with their own; are precluded from reassessing the evidence; and are likewise barred from criticizing the selection and interpretation of the applicable substantive law and, where relevant, the subsumption of the facts under that law – even where mandatory EU rules are at stake.

However, this minimalist approach to reviewing arbitral awards appears to conflict with the principle of primacy of European Union law, as reflected in Organic Law 7/2015 of 21 July, which amended Organic Law 6/1985 of 1 July on the Judiciary by introducing Article 4 bis, providing that: “1. Judges and courts shall apply European Union law in accordance with the case law of the Court of Justice of the European Union.”

As Spain is a member state of the European Union, it is unquestionable that EU law must be taken into account when defining public policy as a basis for setting aside an arbitral award (Article 41.1(f) of Arbitration Act 6/2003 of 23 December). The Constitutional Court itself, in Judgment No. 46/2020 of 15 June, held that public policy includes “fundamental rights and freedoms guaranteed by the Constitution, as well as other essential principles unavailable to the legislature due to constitutional requirements or the application of internationally accepted principles.”

The CJEU has also held (Judgment of 26 February 2013, Case C-617/10, Åklagaren, paragraph 46):“Any provision of a national legal system or any legislative, administrative or judicial practice that would reduce the effectiveness of EU law by denying the court having jurisdiction to apply that law the power to do everything necessary, at the moment of its application, to set aside national legislative provisions that might prevent EU rules from having full effect would be incompatible with the requirements inherent in the very nature of EU law (see judgment in Melki and Abdeli, paragraph 44 and the case law cited).”

Thus, in contrast to the Constitutional Court’s minimalist doctrine, the CJEU imposes, in certain cases, a somewhat more substantive – albeit still limited – review on the merits (in iudicando). Courts must be able to examine fundamental provisions of EU law and, where appropriate, make a request for a preliminary ruling (see, inter alia, CJEU judgments of 6 March 2018, Case C-284/16, Achmea, paragraph 54; 7 July 2016, Case C-567/14, Genentech, paragraphs 26–27; 1 June 1999, Case C-126/97, Eco Swiss, paragraph 35, 36 and 40; and 26 October 2006, Case C-168/05, Mostaza Claro, paras. 34–39). It should not be overlooked that the CJEU has already made clear that arbitral tribunals lack the authority to make references for a preliminary ruling, as they are not courts or tribunals of EU Member States (see CJEU judgments of 23 March 1982, Case C-101/81, Nordsee, paragraph 14; 6 March 2018, Case C-284/16, Achmea, paragraph 49; and 27 January 2005, Case C-125/04, Denuit and Cordenier). Therefore, it must be the courts reviewing arbitral awards that are able, within limits, to examine the application of EU law and, if in doubt, refer questions to the CJEU to ensure the unity of EU law. The aim is to prevent arbitration proceedings from creating a sphere immune from the proper application and supervision of EU law.

Judgment No. 146/2024 has been welcomed by part of the academic community as a reaffirmation of the Constitutional Court’s case law in favour of protecting party autonomy in arbitration. However, it has also been criticised in equal measure due to the tensions it raises within the framework of European Union law.

The debate has intensified further as the High Court of Justice of Madrid (TSJM), which must now issue a new judgment on the action to set aside the award, has – despite Judgment No. 146/2024 – decided to refer a preliminary question to the CJEU (Order No. 4/2025 of 20 March 2025). Specifically, it asks whether it is compatible with Articles 47 and 51(1) of the Charter of Fundamental Rights of the European Union, Article 19 of the Treaty on European Union, and the principles of primacy, effectiveness and unity of EU law, for judicial review of an arbitral award based on infringement of fundamental EU public policy rules to be:

  • purely external, without the court being able to review, with full jurisdiction, the arbitrators’ decision not to apply mandatory EU law;
  • purely external, without the court being able to review, with full jurisdiction, whether the arbitrators have correctly applied mandatory EU law; and
  • limited by the doctrine and criteria established in Judgment No. 146/2024.

More recently, in the context of a second arbitration between the same parties concerning the same contractual clause – resulting in a new award that was also challenged – the TSJM has submitted a second request for a preliminary ruling in Order No. 11/2026 of 23 March 2026. According to the court, “the external review to which the Constitutional Court confines our scrutiny of the proper application of mandatory EU law effectively leads, in practice, to each arbitrator being able to choose whether or not to apply EU law and how to interpret it, without a judicial mechanism to verify its conformity, for example, with the clear and settled case law of the CJEU.” It further adds: “this Chamber cannot see how the primacy of EU law can be guaranteed in a specific case if it is not empowered to assess, with full jurisdiction, whether the arbitral tribunal has improperly excluded the application of EU law – consistent with CJEU case law – and, where EU law is applicable, whether it can be declared that the contested clause is anti-competitive ‘by object’ without having verified any of the elements that the CJEU requires to be examined.”

This debate is not only important for Spain but for all member states of the European Union, as the ruling ultimately delivered by the CJEU will be binding on all national courts within the EU.

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Broseta Abogados was founded in 1975. It is a full-service business law firm with a strong reputation in the Spanish and Iberian legal markets. The firm advises domestic and international corporations, financial institutions, investment funds, public sector entities and family-owned businesses on complex legal and regulatory matters. Broseta operates through offices in Madrid, Valencia, Barcelona, Lisbon and Zurich, providing clients with extensive coverage across key business and financial centres. The firm brings together more than 300 professionals, including lawyers and multidisciplinary specialists, organised into highly specialised practice groups that deliver expert advice across all areas of business law. The firm is particularly recognised for its client-focused approach, combining technical excellence with a deep understanding of industry sectors and commercial objectives. Through its membership in the Ibero-American Legal Network, Broseta offers clients coordinated legal support across multiple jurisdictions, strengthening its ability to assist businesses with cross-border transactions, international expansion projects and multi-jurisdictional matters throughout Europe and Latin America.

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