Can International Investment Agreements Protect Investments in Non-Territorial Waters? —Institutional Foundations, Jurisdictional Analysis, and Pathways for Improvement

Xingyi Duan¹Ziheng Liu^2*

• ¹Dalian Maritime University Law School, Dalian, China
• ²School of Foreign Studies, China University of Political Science and Law, Haidian, China

The adoption of the United Nations Convention on the Law of the Sea (UNCLOS) and subsequent developments in State practice have prompted a growing number of International Investment Agreements (IIAs) to include "definition of territory clauses," extending their legal applicability beyond territorial waters. Yet the fragmented nature of the IIA regime has resulted in significant variations in the formulation and substantive scope of these provisions across different treaties. Concurrently, persistent divergences persist among States regarding the interpretation of sovereign rights and jurisdiction exercisable in various maritime zones—including the exclusive economic zone, continental shelf, high seas, and the international seabed Area—which fundamentally shapes the applicability of IIAs to investments in non-territorial marine spaces. Determining such applicability carries broader implications for the interpretation and implementation of UNCLOS, particularly concerning marine environmental protection obligations and dispute settlement mechanisms. This complex legal interplay calls for rigorous scholarly analysis and coordinated policy responses. The international community should take proactive steps toward prescriptive and practical reforms to clarify the application of IIAs to investments in non-territorial waters. When properly defined and implemented, extending IIA protections to maritime investments could not only promote sustainable blue economic activities but also strengthen the international rule of law in ocean governance.