Reflections on the Presence of Third States in International Maritime Boundary Delimitation

Abstract

The presence of third States occurs when two countries delimit their maritime boundary in a maritime area where there are more than two coastal States. The bilateral nature of maritime delimitation between two States requires the delimitation process not to prejudice the legal rights and interests of third States. On the one hand, at the procedural stage of international adjudication, third States may file an application for permission to intervene in the proceedings before a court or tribunal; at the merits stage, a third-party judicial organ may leave undecided the endpoint of a final boundary line to be delimited, so as not to affect the rights of a third State. On the other hand, in interstate maritime boundary agreements through international negotiation, in order to take care of third States' legal rights and interests, States may adopt several ways of addressing the existence of tripoints. This paper, in four parts, discusses the presence of third States in international maritime boundary delimitation. The first part gives a definition of a third State in the framework of maritime delimitation. The second part reflects on international adjudication relating to the presence of third States. The third part provides some observations on State practices relating to the existence of tripoints. The conclusion points out that there is a widening gap between maritime delimitation in theory and in practice, since recent case law particularly confines the delimitation to a purely bilateral status, without enough focus on the presence of third States, resulting in procedurally prejudicial impacts upon the legal rights and interests of third States.