The biodiversity, health and services of European marine ecosystems is severely threatened as cumulative human pressures and impacts continue to spread and increase throughout our seas and along our coasts. In order to put biodiversity on the path to recovery and thus achieve the ambitious policy goals set out by the EU Green Deal and the Biodiversity Strategy 2030, we need well informed science advice and operational decision-support tools allowing end-users to decide on conservation actions for biodiversity protection (e.g., MPAs), while at the same time seek to minimize trade-offs with other human use of ocean space (e.g., fishing, off shore energy and shipping). B-USEFUL will develop and deliver user-oriented solutions fit for uptake and implementation in decision making by effectively building upon existing European data infrastructures and governance frameworks for ecosystem-based management advice and marine spatial planning. This will be achieved by delivering upon the following objectives (here presented in short form) addressing the expected outcomes and impacts of the call and destination, namely to: (i) identify end-user needs; (ii) co-develop biodiversity indicators, targets and scenarios; (iii) create a standardized biodiversity and pressure data base; (iv) assess the status and cumulative impacts on biodiversity; (v) quantify risk and vulnerability to biodiversity loss; (vi) perform model forecasts of changes in biodiversity and ecosystem services; (vii) co-develop an interactive, online decision-support tool fit for management strategy evaluation of actions ensuring biodiversity protection. The project will embrace a process of co-creation where all outputs are iteratively co-developed, validated and approved by end-users. This serves not only to build mutual trust and credibility, but also facilitate direct uptake and implementation of the user-oriented tools and knowledge within operational decision-making for marine management and conservation.