THE INTERACTION OF TREATY AND CUSTOM IN THE CONCEPT OF OFFSHORE ARCHIPELAGOS

Abstract The law of the sea has long been a rich source of examples of the interplay, and occasional entanglement, of treaty and custom. This article discusses whether claims to close off the waters of ‘offshore archipelagos' by non-archipelagic States are consistent with international law against the background of this perennial issue. Analysis of the 1982 Law of the Sea Convention (LOSC) demonstrates quite clearly that there is no basis for such claims. ‘Going beyond the LOSC’ the article examines whether the matter remains subject to customary international law; whether subsequent practice may have established the agreement of the parties that the relevant provisions of the LOSC are to be interpreted as allowing their invocation by non-archipelagic States with offshore archipelagos; and whether there is ‘supervening custom’ that may have emerged since the adoption of the LOSC and that permits such claims by non-archipelagic States. Identifying and critically assessing the current state of international law on these fundamental questions of the relationship between treaty and custom, it is concluded that there is no basis for arguing that non-archipelagic States are able to claim any sort of special status for ‘offshore archipelagos’.