This chapter investigates the intersection of militarization, colonialism, and insularity, focusing on the Italian islands of Sardinia and, more briefly, Sicily within a global framework. It explores how islands, historically marginalized as sites of extractivism and exclusion, have become strategic military locations due to their geographic isolation. Militarized islands exemplify a “double dependency,” reflecting their subaltern positions in global and national geostrategic hierarchies. Drawing on postcolonial theories, the chapter examines the transformation of natural spaces into military zones, highlighting the socio-political and environmental impacts of such practices. The chapter critiques the interplay of secrecy, ignorance, and risk in military operations, emphasizing how invisibility facilitates environmental degradation and public health crises. It also explores cultural alienation through the militarization of local landscapes, analyzing how renaming and repurposing spaces disrupt community identities and histories. Finally, the chapter addresses the role of greenwashing and territorial branding in legitimizing military activities while obscuring their consequences. By situating Sardinia within a broader discourse on coloniality and militarization, the chapter connects its experience to global patterns, such as US military practices in the Pacific. It finally posits the militarization of Sardinia as a colonial practice, characterized by unequal distribution of risk, pollution, and land expropriation.