The project aims to improve sustained and multipurpose ocean observations needed for European and global climate requirements. It develops an enhanced framework for nations’ contributions to observing Essential Ocean Variables (EOVs) and Essential Climate Variables (ECVs), supporting improved regional and global climate assessments, projections, and actionable indicators for sustainable development. The project also integrates ocean observing data with Earth System modelling, promotes interoperable data standards and FAIR/CARE data practices, and contributes to initiatives such as the EU Mission “Restore our Ocean and Waters”.