The South China Sea (SCS) is a conflict-ridden international arena of rivalry between China, the US, India, and the other ASEAN countries over sovereignty, resources and security. In this geo-political clash China is the dominant force and Vietnam its main challenger. While most analysts assume that the various claims to the mostly uninhabited islands are motivated by the presence of submarine mineral resources, the conflicts evoke strong nationalist feelings in Vietnam and China, fuelled by narratives of the historical presence of fisheries and navies. By analyzing the tension between complex territorial claims, new technologies and forms of knowledge applied by these states to delineate their material borders on the sea and vernacular notions of social space, this paper explores how sovereignty and nationality is enacted on a day-to-day basis. Thus, I argue that maritime territorialisation is a paradox of treating the sea as ‘land’ produced by the performance of a socially constructed image of the state geo-body capitalizing on strong nationalistic sentiments in China and Vietnam.