The interpretation and applicability of the islands regime under the United Nations Convention on the Law of the Sea (UNCLOS) has always been a question for debate.[1] This is proved again in the South China Sea Arbitration Case between the Philippines and China. An associated question is how much weight an island may be given in maritime delimitation. It is an utmost challenge, if not impossible, to define the legal status of each individual insular feature in the South China Sea and to evaluate the effect of them on maritime delimitation. Applying the concept of the archipelagic regime to the archipelagos in the South China Sea may provide an alternative breakthrough. However, this will raise the question of whether a continental State’s outlying archipelagos enjoy the status of the archipelagic regime as defined in Part IV of UNCLOS.

This article traces the drafting history of the regime of the archipelagic State defined in UNCLOS, and analyzes the legal implication on the concept of archipelagic baselines, the legal status of archipelagic waters, the right of innocent passage, and the right of archipelagic sea lanes passage. It further examines the practice of continental States in their dependent archipelagos and identifies potential developments with respect to the endorsement of the archipelagic concept in the law of the sea.

In the South China Sea Arbitration Case, the Tribunal rules out the possibility of treating the geologically defined archipelago of Nansha Qundao (Spratly Islands) as a single unit that China seems to claim as having the status of an archipelagic regime. China argues that under its administration, the four archipelagos have been a single unit and should enjoy the status of an archipelagic regime. This article argues in favor of the applicability of the archipelagic regime in the Nansha archipelago for the following reasons. First, it meets the criteria for a political, security, and economic entity with interconnectedness. Second, the historic criterion for the identification of the legal archipelago is provided as an alternative in the case that an archipelago cannot meet the other requirement. The four island groups in the South China Sea have been governed as a single entity throughout China’s administrations. Third, there is an emerging customary rule relating to the application of straight baselines to continental States’ outlying archipelagos. Fourth, one of the key elements of an archipelagic regime is the principle of balancing exclusive and inclusive interests of archipelagos (exercise of sovereignty) vis-à-vis those of third States (navigation, traditional fishing rights, etc.). Applying the legal concept of an archipelagic regime to Nansha will serve to guarantee this important principle of balance.