Spain ratifies Protocol 16 to the European Convention on Human Rights

Spain has completed the ratification of Protocol No. 16 to the Convention for the Protection of Human Rights and Fundamental Freedoms, whose instrument was published in the Official State Gazette (BOE) No. 224, of 17 September 2025. The agreement, concluded ad referendum in Strasbourg on 2 October 2013, received prior authorization from the Congress of Deputies and the Senate, and Spain accompanies it with Declarations. With the entry into force of the Protocol, the country’s highest courts may request advisory opinions from the European Court of Human Rights.

Protocol No. 16, promoted within the framework of the Council of Europe, creates a channel for cooperation between the highest jurisdictions of the States Parties and the court based in Strasbourg. In pending cases, questions of principle concerning the interpretation of the rights recognized in the Convention may be referred to the European court, thereby reinforcing the coherence of case law and the protection of rights in domestic judicial proceedings.

The parliamentary procedure was reflected in the official publications of the Cortes Generales. The text of the agreement was published in the BOCG Cortes Generales, Series A, No. 130, of 14 March 2025, and the Chambers authorized the expression of the State’s consent on the following dates:

• Congress of Deputies: authorization granted on 14 May 2025 (BOCG Congress of Deputies, Series C, No. 61-3, of 22 May 2025).
• Senate: authorization granted on 11 June 2025 (BOCG Senate, Section III, No. 274_2529, of 16 June 2025).
• Official State Gazette: publication of the instrument in No. 224, of 17 September 2025.

A new channel before Strasbourg

Protocol No. 16 allows the highest courts of the States Parties to request advisory opinions from the European Court of Human Rights on questions of principle relating to the interpretation or application of the rights and freedoms of the Convention, in cases pending before them. This is a mechanism for judicial dialogue that complements, prior to the ruling, the classic avenue of the subsequent individual application.

The instrument ratified by Spain incorporates the Declarations that the Kingdom of Spain wishes to make, as recorded in the list of international agreements processed by the Cortes Generales during 2025. The publication of the instrument in the BOE concludes the internal procedure for expressing the State’s consent initiated with the text published in the BOCG Cortes Generales, Series A, No. 130.

Relevance for the protection of rights

For citizens, ratification of Protocol No. 16 means a reinforcement of the protection of fundamental rights in judicial proceedings. Spanish higher courts will have an additional instrument to consult Strasbourg in cases raising questions of principle, which can anticipate uniform interpretations, reduce litigation and prevent subsequent convictions by the European Court of Human Rights. The instrument completes the network of Convention instruments that Spain had already incorporated into its legal system, and deepens the link between national and European justice.

Source: Official State Gazette (Boletín Oficial del Estado), No. 224, of 17 September 2025 (official reference: Protocol No. 16 to the Convention for the Protection of Human Rights and Fundamental Freedoms, done ad referendum in Strasbourg on 2 October 2013). Text of the agreement: BOCG Cortes Generales, Series A, No. 130, of 14-III-2025.