Estuaries connect terrestrial and marine biomes. Their ecological functioning is essential for marine matter fluxes, while their central economic role as transport hubs persists throughout history and has become ever more pronounced. Managing complex socio-ecological systems such as estuaries can benefit from an ecosystem service approach. The challenge is to combine highly complex knowledge, prone to uncertainties, to policy relevant information. This paper introduces a knowledge-based ecosystem service screening, applied in a participatory manner by including different stakeholders from four industrialized NW-European estuaries.The approach allowed to efficiently engage stakeholders from different, often opposing sectors, in order to derive a set of ecosystem services of high societal importance, link them to supply by habitats, and explore inter- and intra-estuarine variability. By introducing the notion of trade-offs and synergies and assessing these for estuaries, the interconnectedness and mutual interests for estuarine management measures were indicated. The screening is based on knowledge surveys among experts. Statistical reliability was acceptable, but to complement the assessment, quantitative validation on a local scale would be useful.Ecosystem service assessments, especially when engaging stakeholders, can inform policy on strategies for the sustainable use of ecosystem services in intensively used and ecologically fragile estuarine zones.