This article analyzes ECS maritime disputes through two lenses: as a globally comparable case study mediated through LOS and as a distinct regional case that difers in several respects from disputes outside East Asia. This study focuses on the Senkaku/Diaoyu island dispute but also examines broader EEZ and ADIZ disputes between China, Japan, and South Korea and the Ieodo dispute between China and South Korea. It fnds that global dynamics are applicable to the ECS disputes, as countries depend on LOS rules even while attempting to interpret them for unilateral advantage whenever possible, and parties avoid formal arbitration, when possible, in favor of bilateral agreements. However, regional factors impact these dynamics. The sudden and sometimes violent transition from the SinoCentric tributary system to the Westphalian system has undermined the legitimacy of LOS and western international law regionally. Finally, the presence of China as a party to almost all ECS disputes limits the application of LOS because China’s position as a near-peer competitor with the US gives it additional options to unilaterally impose its will. Unlike relatively weaker parties to these disputes, China may be less concerned about fouting LOS that it does not see as necessary for protecting its maritime claims.