The five EOSC Science Clusters are collaborations of different but closely related discipline specific Research Infrastructures (RIs) organisations set to promote efficient interdisciplinary collaboration and implement the open science agenda. The services developed by the Science Clusters are cornerstones of the emerging EOSC ecosystem, as outlined in their position paper. 

All five Science Clusters are core members of the OSTrails technical team, and are represented by one or more RIs and organisations, and a coordinator/ representative/ liaison: ENVRI – Environmental Science (Joaquin López Lérida, LifeWatch); EOSC-Life – Life Science (Susanna-Assunta Sansone, ELIXIR, UOXF); ESCAPE – Astronomy (Baptiste Cecconi, OBSPM); PaN – Photon Neutron Science (Renaud Duyme, ESRF); SSHOC – Social Sciences and Humanities (Daan Broeder). The clusters coordinate their input for the OSTRails infrastructure building but also ensure that their individual requirements and existing relevant services are part of the fabric of the Plan-Track-Assess process. Wider engagement within clusters also happens by running thematic pilots co-create, implement, validate, and adopt OSTrails results.