EU-INTERCHANGE addresses the outcomes of the call “CL6-2024-CLIMATE-01-6: Ocean models for seasonal to decadal regional climate impacts and feedbacks”. A current limitation to climate change projections for EU-basin scale to coastal use comes from an insufficient representation and resolution of basin and coastal ocean dynamics and from an unsatisfactory understanding of the oceanic biogeochemical cycle. Most climate models include the ocean dimension that stops at the regional scale as defined by meteorology and climatology like in CORDEX. In parallel, operational oceanography centres develop and operate ocean models (physics, biogeochemistry, sea-ice) for daily ocean forecasting and reanalysis that represent more exhaustively the full ocean dynamics. Methods should help close the gap between current climate projections (global, centennial) on the one hand and existing Copernicus Marine physics and biogeochemical models used for daily ocean forecasting.