Coastal management aims to mitigate the pressures on coastal zones (e.g. intensification of anthropogenic pressures, climate change) while increasing the socioeconomic benefits the coastal region has to offer. Monitoring the coastal zone is therefore fundamental for effective coastal management. In light of gaps, citizen science can play an important role by increasing the sampling coverage in coastal zones. The OCLM (Observatoire Citoyen du Littoral Morbihannais - Morbihan Coastal Citizen Observatory) stands as the pioneer citizen observatory dedicated to monitoring the physical changes along France's coastline, remaining the sole initiative of its kind in the country. The OCLM objective is to examine, survey and comprehend the coastal evolution to adjust its management (mainly using nature-based solutions), all the while engaging and collaborating with citizens, policymakers and scientists.