Efficient and effective use of offshore renewables is pivotal in the transition of the EU to become a net-zero economy in greenhouse gas emissions by 2050. EU-SCORES will unlock the large-scale potential of the roll-out of offshore renewable energy in multi-source parks across different European sea basins through two highly comprehensive and impactful demonstrations: (1) An offshore solar PV system in Belgium co-located with a bottom fixed windfarm and; (2) A wave energy array in Portugal co-located with a floating wind farm. The multi-source demonstrations in EU-SCORES will showcase the benefits of a continuous power output harnessing the complementarity between wind, sun and waves as it leads to a more resilient and stable power system, higher capacity factors and a lower total cost per MWh. These aspects will also improve the business case for the production of green hydrogen within these parks. The full-scale demonstrations will prove how the increased power output and capacity installed per km2 will reduce the amount of marine space needed, thereby leaving more space for aquaculture, fisheries, shipping routes and environmentally protected zones. Additional benefits attained by co-using critical electrical infrastructures and exploring advanced operation and maintenance methodologies supported by innovative autonomous systems will further lower the costs per MWh. The involvement of major project developers and utility companies (EDP, EGP, SBE, RWE, EnBW, Eneco, OceanWinds, and Parkwind) will ensure an accelerated path towards commercialisation of these innovative parks. Altogether, through a highly competent, skilled and motivated consortium EU-SCORES will pave the way for bankable multi-source parks including wind, wave and floating solar systems across different European sea basins by 2025, thereby supporting the stability and resilience of the European energy system, while considering sustainability, local stakeholders and existing ecosystems.