This article considers the phenomenon of ‘state-extinction’: a situation in which a state faces a very real and imminent threat of literal disappearance from the surface of the Earth. By looking at the case of sinking small island states, this article explores the role and meaning of territory to statehood, while advancing the idea that rather than as a claim-right to territory, the situation of sinking island states should be understood through a state-right to exist as a state – an internationally recognised political authority – in the system of states. If and when this is the case, states under the threat of physical state-extinction may have claims towards international community to continuing existence as political entities without necessarily having a right to new territory.