This article analyses the relationship between environmental security and sea level rise, and its impacts on Small Island Developing States (SIDS), particularly in the case of Tuvalu. Specifically, it discusses the existential threat this phenomenon poses to island states, concluding with the importance of adaptive capacity in a holistic approach. Throughout the article, the legal regimes of islands and artificial islands are analysed, and various ways in which disappearing states can seek to prolong their existence are identified. The article also reflects on the importance of the territorial element in recognising a state and discusses the development of the idea of virtual sovereignty proposed by Tuvalu.