Long dependent upon imported fossil fuels, the islands of the Caribbean have recently been targeted by initiatives meant to hasten a shift to more renewable forms of energy. In this paper, we provide an overview of this ongoing energy transition, focusing on the experiences of Jamaica and the Eastern Caribbean. To do so, we develop the concept of the ‘island energy metabolism’ as a way to conceptualize relationships between the biophysical properties of different energy sources and the distinctive territorial, infrastructural and geopolitical characteristics of islands. We trace the development of the prevailing fossil fuel-based metabolism in the Caribbean region, and highlight some of the resulting energy dilemmas faced by island territories in the region. We then turn our attention to the ongoing renewable energy transition, focusing on the opportunities and barriers posed by islands. We highlight the role of island imaginaries in attracting international interest, and point to the ways in which island geographies can hinder the transition. Drawing on examples gleaned from fieldwork in the Caribbean, we discuss the financial, logistical and infrastructural challenges posed by the region’s fragmented sovereignty and island territoriality, and suggest how a metabolism lens can shed light on the trajectories of low-carbon transitions.