OSIRISC is the integrated observatory of systemic vulnerability to coastal risks of erosion and marine flooding in Brittany. OSIRISC approach considers all components of vulnerability: hazards, exposure, risk management and social representations. Using data in various formats, from reference databases and satellite imagery to in situ measurements and surveys with questionnaires, etc., OSIRSIC “measures” these four components over time, with indicators that were co-designed by researchers and risk management stakeholders. Data collection is collaborative, relying both on academics and local risk management authorities, which are involved in the formal partnership Litto’Risques that is meant to enable capacity-building. OSIRISC provides technical and methodological support for collaborative observation and decision-aid for management of coastal erosion and marine flooding risks, as well as training, low-cost instrumentation for field observation protocols, data dissemination through web platforms OSI and MADDOG and networking. The success of OSIRISC observatory relies on the close interaction between academics and local authorities, which requires in-depth involvement of both parties in joint actions (data collection, sharing expertise, …), as well as political support to achieve partnership agreements and engage in long-term observation.