The objective of the project SWOS is to develop a monitoring and information service focussing on wetland ecosystems.Globally wetlands are the ecosystems with the highest rate of loss. This is alarming, considering their significance as biodiversity hotspots and ecosystems with a central role in the water cycle, including improving water quality and reducing water scarcity, in climate regulation and the economic benefit gained from using their services.A key limitation to their more effective conservation, sustainable management and restoration is the missing knowledge underpinning the application of European policy by Member States. Under the Biodiversity Strategy, Member States have recently committed to the mapping and assessment of ecosystem services (MAES); this provides a key instrument for an improved integration of wetlands in policy.SWOS will take full advantage of the Sentinel satellites and integrate results from the ESA Globwetland projects. Status maps and indicators, as well as near real-time observations will allow the assessment of biodiversity and the monitoring of dynamic changes in an unmatched temporal and spatial resolution.The Service Portal will allow the integration and web-based analysis of new maps and in-situ measurements and provide a unique entry point to locate, access and connect existing information and databases. It follows a GEOSS compatible data-broker approach and adopts international standards.SWOS contributes to establishing a Global Wetland Observing System, as requested by Ramsar, it will facilitate local and EU monitoring tasks and input into international reporting obligations. SWOS will position Europe in a leading role for wetland activities within the GEO ecosystem, biodiversity, water, land cover tasks. The direct involvement of users working at different scales and support of key user organizations ensures the usability and acceptance of the service, the harmonization with related activities and a long-term impact.