What is territoriality, if we consider it from a maritime, rather than landed perspective? And how should borders be reconsidered, if we assume that the nonsovereign space of world seas is constitutive of politics, rather than exceptional to it? To answer this question, this chapter adopts a processual approach to international legal theory and outlines a vast trajectory. Sources from antiquity display an imagination of maritime spaces as an exteriority in relations to politics. In the seventeenth and eighteenth centuries, classical international lawyers formulated an international law of the sea that sought global applicability. This was what is called here “the first internalization” of the sea. A second internalization is currently underway, in which a central tenet of the first, freedom of movement at sea, is now being questioned. It is argued in this chapter that if we are to understand territoriality, we must reject the premise of universal territoriality and understand it (also) from the position of nonterritoriality which is offered to us by the sea. In other words, the two internalizations are crucial for a processual understanding of territoriality. The chapter concludes with reflections on how traces of exteriority, beyond both internalizations, can be utilized for the purpose of political action.