This policy brief highlights OPERAS’ role in promoting Diamond Open Access (OA) as an equitable, community-led, and resilient model for scholarly publishing. Diamond OA ensures research is freely accessible to all, removes author fees, and fosters diverse, community-controlled publishing ecosystems. OPERAS contributes to EU Open Science priorities through initiatives such as the European Diamond Capacity Hub (EDCH) and Horizon Europe projects (CRAFT-OA, DIAMAS, ALMASI), coordinating standards, capacity building, and collaboration across national and European levels. By integrating Diamond OA into the European Open Science Cloud (EOSC) and supporting National Capacity Centres, OPERAS strengthens skills, infrastructure, and strategic alignment, ensuring sustainable, interoperable, and inclusive open scholarly communication. The brief emphasises the need for targeted policies, coordinated efforts, and sustained funding to secure Diamond OA as a cornerstone of equitable and FAIR European research practices. This policy brief is currently under review by the European Commission.