The International Center for Advanced Studies on River–Delta–Sea Systems DANUBIUS-RI is a pan-European distributed research infrastructure supporting interdisciplinary research on large river-sea systems. DANUBIUS-RI will fill the gap of fragmented research on European research on river-sea systems, drawing on existing research excellence across Europe, enhancing the impact of European research while maximizing the return on investment. It will provide access to a range of European river-sea systems, facilities and expertise; a ‘one-stop shop’ for knowledge exchange in managing river-sea systems; access to harmonized data; and a platform for interdisciplinary research, inspiration, education and training. DANUBIUS-RI will offer a source-to-sea perspective to resolve problems arising from human impacts on River-Sea-Systems.