The Strait of Melaka and connected waterways have been critical to, and directly affected, the formation of littoral states, societies and economies in eastern Sumatra, the Riau Islands, the Malay Peninsula, and Singapore. The history and nature of statehood in the region is interrelated to the way in which naval capabilities evolved, but, as argued in this article, perhaps not in the straightforward fashion often assumed. Naval capabilities and strategies evolved in tandem with state policy to adapt to changes in the wider Asian maritime political economy which was dominated at various times by China and India. This article examines the factors that affected maritime policy in the Melaka Straits c. 500 to 1500 CE, and the extent to which these furthered the viability of the mainly Malay port-polities, and in particular the regional hegemonic state of Srivijaya in eastern Sumatra. The study utilises textual records, epigraphic materials, and literature to reconstruct a more nuanced picture of maritime states and naval power in premodern Southeast Asia.