Small island developing states are often characterized as vulnerable owing to their unique geographies of smallness and remoteness, resource insecurity, and more recently from the impacts of climate change. These vulnerabilities are often manifested in resource insecurity, significant imports, poor waste management, and the inability to develop economies of scale. In effect, sustaining small islands in an era of global environmental change is a task both scholars and policy makers are increasingly grappling with. Can small islands be sustainable? This research examines the social metabolism of an island system, and introduces the concept of “socio-metabolic vulnerability”. As such, this research provides novel insights into the linkages between patterns of resource-use, systemic risks and vulnerability. Results from a local material and energy flow analysis (local-MEFA) for the island of Ndzuwani (Comoros) suggest a very low level of resource-use but at the same time heavy reliance on critical imports that cover vast distances, that are vulnerable to price and climate shocks. Informal activities in resource extraction play an important role in lending both vulnerability and resilience to Ndzuwani. This study adds to the scarce body of literature that argues that small island economies would need to leverage resource-use patterns to build system resilience, along with bold policies and institutions that support material circularity, engage communities and fosters frugal innovation.