The UNITED (multi-Use platforms and co-locatioN pilots boosting cost-effecTive, and Eco-friendly and sustainable production in marine environments) project provides evidence by means of pilot demonstrators that the development of multi-use platforms or co-location of different activities in a marine and ocean space is a viable approach (economically, socially and environmentally) for European maritime industry and local ecosystems. The main activities centre around 5 pillars defined through the BG-05 call (i.e. Technology, Economy, Legal/Governance/Policy, Society, and Environment). The technological pillar comprises the need for synchronization of multiple operation and maintenance systems, local market stakeholders impact, support in management and planning decisions for new developments, as well as improvements in current design, safety and infrastructure set-ups for multi-use extensions. The economic pillar will investigate insurance issues, profitability/threshold to finance/investment pay off of multi-use developments while also paying consideration to risk/health impact on business, zoning and offshore, and economic sustainability. The Legal/Policy/Governance pillar focuses on the lack of dialogue between public institutions which issue permits; the lack of health and safety regulation and standards for multi-use, zoning and offshore as well as the absence of a framework for legal responsibility in multi-use. The societal pillar includes societal debates and concerns, societal perception of multi-use social preference of multi-use versus single use, societal ownership and acceptance issues, trust issues between sectors, required improvements in professional skills and competences. The environmental pillar includes determining the impacts of the various structure designs and the overall environmental feasibility of the pilot site developments and implementation regimes.