Globally, Indigenous Marine Areas are contributing to ocean sustain-ability by protecting key habitats and species whilst safeguarding customary uses for local communities. They are emerging as one of the key political mechanisms that can counteract the ravages of the blue Anthropocene.
Nevertheless, their contributions are threatened by the accelerating expansion of economic activities, and exclusion-ary marine governance systems, affecting both marine biodiversity and human wellbeing. In southern Chile, indigenous communities have been countering the expansion of the salmon farms by promoting the establishment of Espacios Costeros Marinos para Pueblos Originarios (here called Indigenous Marine Areas or IMAs). These IMAs are being developed by coastal communities to protect traditional or customary coastal uses, and revitalizing culture whilst contributing to marine conservation. Using a relational theoretical approach and mixed methods, the paper presents the major trends in the implementation of IMAs in Chile. Through the case of the Los Lagos Region, it shows how the action-network that pursued the designation of IMAs is continuing today. The paper stresses the role of conservation assemblages to lead collective actions, showing how these constellations of agents have been interacting during the decision-making process and institutional building, whilst promoting the establishment of IMAs as place-based democratic mechanism to promote the sustainability of the southern Chile.