Small islands are among regions most affected by the impacts of global climate change. They are regarded as particularly vulnerable, but from a different point of view, island societies also feature a particular sociocultural resilience, which distinguishes them from continental societies. How do social structures increase the adaptive capacity of small islands towards sea‐level rise? I consider the concept of social capital as applicable in order to understand the role of communities and collective action in a context of vulnerability and resilience. In this paper, I present results from a case study on the Isles of Scilly, UK. A mixed methods qualitative approach has been applied to analyse the various roles of social capital for the adaptation to climate change impacts on this small archipelago, which is representative of European small islands in an economically advanced, but isolated context. The Isles of Scilly are among the most vulnerable island regions in Europe. The results of the research contribute to the general discussion on social capital and the relevance of collective action for the adaptation to global climate change. How useful is the concept? And how relevant is it for small islands, such as the Isles of Scilly?