This paper uses a spatial approach to construct a history of the Red Sea islands of Tiran and Sanafir, which lie at the entrance to the Gulf of Aqaba and whose borders were never delimited until April 2016, as a way of understanding the public outcry against the Saudi-Egyptian maritime border agreement that determined the islands fell within Saudi territorial waters. Using published archival documents from the British Foreign Office, reports from international organizations, and news accounts, as well as studying the political rhetoric of regional leaders on the status of the Gulf of Aqaba, this paper argues that the modern history of Tiran and Sanafir Islands, from the mid-nineteenth century through to present times, is one of a series of competing and complementary processes that transformed the islands into an ambiguously defined space for power, even identity, competition. Driven by evolving political interests, Tiran and Sanafir Islands became sites of rival visions of political organization as various emerging powers—including British, Ottoman, Egyptian, Israeli, and Saudi authorities—sought to define borders or competed over access to the Gulf of Aqaba. The islands were subjected to successive processes of territorialization (associating political authority with territory), geopoliticization (giving territory significance in the context of imperial or regional power competition), and nationalization (ascribing national identity to territory) that are now in conflict with an emerging neoliberal policy seeking to manage the flow of capital and goods in the Gulf of Aqaba. Each process layered itself over those that preceded it, instituting spatial norms that enhanced or challenged ones prior processes established as well as incorporating the islands and their surrounding geographical space into evolving systems of international organization. In the ambiguity that ensued, the islands and the Gulf were subjected to multiple sovereignization efforts, in which different political entities understood them as sovereignizable and sought to impose competing sovereign and spatial regimes. In the process, the association of sovereignty with territoriality became further entrenched in the political imagination of the region, creating assumptions that the 2016 border agreement overturned. The case of Tiran and Sanafir Islands, thus, demonstrates that the production of modern borders was and remains a fragile and disruptive process because the concepts of sovereignty and territoriality, as spatial configurations, were historically dependent developments that emerged unevenly and independently of each other through contestation, cooperation, conflict, and settlement between various political actors.