This book examines the status of private actors as subjects of law under the rules of the international law of the sea. Providing a methodology for the notion of a single legal personality, it provides a clear understanding of membership in international law in order to establish to what extent private actors can be rights-holders or duty-bearers. It does this by taking a theoretical perspective which allows the reader to interpret their relevance in international law. This unique and innovative work makes a significant contribution to the current scholarly debates on private actors in international law.