At the core of national research and innovation (R&I) ecosystems are research performing and funding organisations, library networks, technological and educational initiatives and institutions. They navigate the complexities of defining local and regional R&I priorities along with aligning policies, services, and community needs with European-wide frameworks. As key drivers of the new European Research Area (ERA), they foster collaboration across disciplines and sectors, bridging gaps and translating high-level policies into actionable practices, and establishing sustainable pathways for the transition towards the Open Science model. 

Recognising this, OSTrails builds on the expertise and know-how of 20 partners, working together in national pilots to integrate Open Science into institutional and national research practices. They develop, operate and/or maintain a variety of Open Science services and infrastructures, including research data management (RDM) platforms, research information systems, archives and assessment tools. These services ensure that research outputs are accessible, discoverable and reusable in the long term. In addition, they apply best practices for discovery, information exchange and FAIR data stewardship adhering to relevant standards to enhance the management and sharing of research outputs and to support the sustainability and interoperability of scientific information and research. Their efforts are reinforced by 16 national research funders, ministries and four national Open Science initiatives, which embed these infrastructures into policies and funding mechanisms, driving systemic change and long-term adoption. 

Central to these efforts is their commitment to EOSC, with over 21 OSTrails partners actively engaged in EOSC governance, contributing to EOSC-Association activities, and national Open Science strategies. Among others, they lead key the EOSC Task Force on FAIR metrics and Digital Objects ensuring national efforts contribute to European Open Science priorities. 

Beyond infrastructure, OSTrails partners provide training and capacity building to support Open Science adoption. OpenAIRE strengthens national networks through its 53 National Open Access Desks (NOADs) and structured training via OpenPlato, while INRIA’s EPOC platform enhances accessibility through mobile learning experiences. 

Recognising that one size doesn't fit all, co-creation activities ensure that national R&I ecosystems are not only aligned with the EOSC framework but also actively contribute to shaping it. Adopting OSTrails results drive interoperability and standardisation, facilitating seamless integration into the EOSC federation and enhancing the collective impact of Open Science. As these systems mature, they bring national ecosystems closer to merging with EOSC nodes, fostering cross-border collaboration and FAIR data sharing.