The Intergovernmental Panel on Climate Change (IPCC) plays a pivotal role in delivering information and knowledge on sea level rise (SLR), a global threat impacting coastlines worldwide. However, considerable disparities still persist in Europe in understanding and applying sea level science, evaluating its repercussions, and devising effective adaptation strategies. These are influenced by local factors such as diverse environments, socioeconomic conditions, policy contexts, and diversity in stakeholder involvement, producing in turn varying knowledge gaps and information needs across European sea basins. In this context, this paper presents the findings of a comprehensive scoping process carried out by the European Knowledge Hub on Sea Level Rise (KH-SLR) to define the outline of the first KH-SLR Assessment Report. It consists of the analysis of stakeholder responses to an online survey and insights shared during four regional workshops, aiming to pinpoint critical gaps in available information on SLR and its potential consequences in European basins, both from a scientific and policy perspective. The analysis was divided into three categories: i) SLR science and information, ii) SLR impacts, and iii) SLR adaptation policies and decision-making. Regarding SLR science and information, many respondents found that significant gaps exist in regional SLR projections and uncertainties, particularly related to long-term SLR induced by potential melting of large icesheets. Interestingly, the perspective on information gaps is different for scientists (emphasizing the need to increase regional projection capabilities) and government users (stressing the availability of accurate projections for their regions). Regarding impacts and hazards, shoreline erosion stands out as a dominant concern in all basins except the Arctic, while emerging issues like saltwater intrusion and the role of SLR in compound risks associated with extreme water levels and river flow were also given significant regional relevance. With regards to policy and decision making, existing adaptation plans are perceived as ineffective and lacking adaptability, with gaps related to underestimated impacts and urban planning. Participants, especially end-users, emphasized the relevance of improved information dissemination and communication to support informed decision-making.