This case study proposes a new methodology for museums to engage and activate marginalised communities, using a social action approach to identify social vulnerabilities and become an actor for equity and justice in the community. The ecomuseum Te Fare Natura in Moorea, French Polynesia, serves its Indigenous community through the social reintegration and cultural rehabilitation of disenfranchised youth. Mediating science through culture and revalorizing ancestral Polynesian knowledges, the ecomuseum collaborates with civic services to hire disadvantaged youth as museum guides, providing them with the skills needed to reclaim their dignity and protect their island homes, building cultural and climate resilience.