On December 5, 2023, Croatia was among the initial group of EU member states to sign the European Declaration on Quantum Technologies, issued under the Spanish Presidency of the Council of the EU in the presence of European Commissioner for Internal Market Thierry Breton. The declaration was formally celebrated at a conference in Brussels on March 22, 2024, under the Belgian Presidency, by which time 21 member states had signed.
Signatory states committed to collaborating on the development of a European quantum technology ecosystem, with stated goals including the coordination of national and regional research programs, acceleration of the transition from laboratory research to commercial applications, and the building of pan-European quantum infrastructures. The declaration also called for support of quantum competence clusters, increased public investment, workforce development, and monitoring of global quantum developments.