The EU-INTERCHANGE project aims to create a Digital Ocean Twin encompassing wave, ocean, biogeochemistry, and nearshore models to evaluate Climate Change impacts across Europe and the Pan-Arctic region. Customized models will be developed to assess mitigation and adaptation strategies, focusing on coastal resilience, impacts of Sea Level Rise, and Blue Economy sectors such as aquaculture and marine renewables. Indicators for marine ecosystem health, blue growth, coastal resilience and societal impacts of Climate Change will be formulated, and used in unique fully automated tools. A large ensemble database spanning from 1995 to 2100, including emission scenarios SSP1 (2.6°C) and SSP2 (4.5°C) using CMIP6 data, will be developed, optimized per European Basin and scale, for all European Seas and the Arctic region. A transparent fully open-source automated service for statistical analysis and reporting will be released to aid decision-making for various stakeholders and applications like coastal protection, marine renewables, food, and tourism. Furthermore, an automated dynamic and statistical downscaling tool will be developed, requiring minimal user expertise but offering the potential for higher fidelity data (<500m), for coastal areas that require further analysis. The novel datasets, both hindcast and forecasts, will seamlessly integrate into COPERNICUS and be openly accessible along with model configurations, fostering collaborative research and informed decision-making regarding Climate Change impacts on marine environments.