Islands are tightly connected to globalized material flows, with specific constraints and vulnerabilities. They are not closed metabolic loops of consumption, production, and waste, favorable to the circular economy. Small islands allow the observation of the material outcomes of circulation, from overflowing dumpsites to marine debris washing up on the shore. We argue that islands are key territories for better understanding the Capitalocene, precisely because of the ways in which they are connected to (rather than isolated from) globalized material flows. This article is a comparative geographical analysis of waste realities in three French/formerly French island territories: Ndzuwani (Comoros), Réunion, and New Caledonia. It builds on metabolism analysis and waste studies—in particular waste colonialism—to address the different perspectives that these approaches open up for the study of island territories. The long-term sociohistorical context of each island helps to explain contemporary waste management policies and practices. A material flow analysis makes it possible to sketch out metabolic profiles that show the contribution of prevailing mining and agricultural industries to waste generation. The comparison of current situations regarding household waste discourses and economies shows how these territories are characterized by waste accumulation.