Since 1983, no non‐self‐governing island connected to a (neo‐) colonial European or American metropole has acquired full Westphalian sovereignty and these islands continue to operate within constitutional frameworks that connect them to these metropoles. Large majorities in referendums on several of these islands have rejected full sovereignty. This paper opens with a review of the essential elements of the concept of sovereignty in a historical and global context, before studying how sovereignty is unfolding in new forms in non‐self‐governing islands in the Pacific and the Caribbean. As a case study, an analysis is presented of how pro‐France (loyaliste) and pro‐independence (indépendantiste) parties in New Caledonia are negotiating sovereignty with France. Evidence is given of how these New Caledonian parties are creatively using classic Westphalian signifiers of sovereignty normally reserved for sovereign states such as flags, diplomatic representations and international treaties, while still negotiating New Caledonia's sovereignty with France. This suggests that in contrast to Westphalian sovereignty, a unique ‘Islandian’ concept of sovereignty is emerging. Islands that are not sovereign in a Westphalian sense can creatively disassemble and reassemble signifiers of Westphalian sovereignty to strengthen their continuous negotiations with their metropoles and their neighbours.