Small Island Developing States are at the forefront of climate change impacts. Low-lying coral atolls in particular are threatened by the combined effects of sea level rise, tropical cyclones, storm surges, high tides, saltwater intrusion, coral bleaching, irregular precipitation patterns, and freshwater salinization. Moreover, many island economies are still marked by the effects of colonialism and great power competition. The extent of future warming will determine habitability of highly exposed areas as adaptation costs are mounting. Pressures on livelihoods and noneconomic losses and damages, such as the destruction of cultural and religious sites, are already occurring. This chapter draws from case studies in the Pacific and the Caribbean and provides examples of how communities are confronting already occurring changes both through in situ adaptation and planned relocation.