This chapter analyses socio-environmental mobilisation in Chiloé in response to proposed extractive projects in mining and energy. It explores how Indigenous and non-Indigenous communities jointly mobilised to defend their territory, drawing on intersecting discourses of ecological protection, cultural identity, and territorial sovereignty. The chapter focuses on the unique repertoire of cross-mobilisation, in which Indigenous rights frameworks—particularly consultation obligations—were used strategically, albeit critically, to challenge extractive expansion. Through a detailed case analysis, the chapter reveals how formal legal rights often fall short when confronted with state and corporate power, prompting communities to develop hybrid strategies that combine legal actions with protest, media engagement, and political negotiation. It also reflects on the tensions between grassroots organising and institutional engagement, highlighting the complexities of advancing environmental justice in contexts marked by historical marginalisation and legal ambiguity. The Chiloé case offers valuable insights into the relational dynamics of legal mobilisation, where rights are not simply invoked but reinterpreted and reappropriated in collective struggles over territory and development.