Can a Global Treaty Protect Waters No One Owns?

About two-thirds of the Earth’s oceans lie beyond any single state’s jurisdiction, waters colloquially known as the high seas. No global treaties have offered a way to set aside protected areas within these vast expanses, until that changed on January 17, 2026, when the Biodiversity Beyond National Jurisdiction (BBNJ) Agreement, entered into force. Also referred to as the High Seas Treaty, its first Conference of the Parties (COP), due within a year, will set the rules forcreating the first high seas marine protected areas (MPAs). These developments raise acumbersome question: what is a protected area worth if the states fishing it never joined the BBNJ?

Part III of the Agreement allows parties to propose area-based management tools, which include establishing MPAs. The COP decides by consensus, or by a three-quarters majority if the former cannot be reached. Decisions take effect 120 days after 60 State ratifications, yet any party may object during that window, making an MPA not truly universal, even among member parties. Non-parties are further removed still. Under Article 34 of the Vienna Convention on the Law of Treaties, a treaty creates no obligations for these states without their consent. The United Nations Convention on the Law of the Sea (UNCLOS) guarantees every county the right to fish and sail freely on the high seas. This means a ship from a country outside the BBNJ Agreement can legally fish in a protected area, as far as the UN is concerned.

The drafters of the BBNJ knew this. During negotiations, countries outside UNCLOS insisted that the new agreement not drag them into obligations they never accepted and leave their legal status untouched. Since the BBNJ binds only its members, the Agreement can only be as strong as the list of countries who join it. If the major fishing nations join, most high seas fishing gains protection. Some have so far, including China and Japan, with The United States having signed but not ratified the agreement.

Even so, the Agreement’s reach doesn’t have to stop at its membership list, and this proposition could extend protected areas to countries that never choose to sign, depending on what parties already control. Each member country must ensure ships registered under its flag follow the rules, but shipowners can dodge this by registering in a country outside the Agreement. Parties could attempt to close that loophole by barring their citizens from working on vessels that fish in protected areas and by denying those vessels port access. If enough countries join, ignoring the rules becomes costly even for ships from non-party states.

The bottom line is that the BBNJ Agreement cannot bind non-member states, so the COP must take action to make their MPAs hard to ignore. This begins by anchoring in port controls and gaining backing support from fellow members to make staying neutral costly. A protected area that binds only the willing is a modest start. In a domain that has never had any protection, this may be a genuine step towards progress.

By: Thomas Goldstein

References

1. Agreement under the United Nations Convention on the Law of the Sea on the Conservation and Sustainable Use of Marine Biological Diversity of Areas Beyond National Jurisdiction, June 19, 2023, U.N. Doc. A/CONF.232.2023/4.
2. United Nations Convention on the Law of the Sea Dec. 10, 1982, 1833 U.N.T.S. 397.
3. Vienna Convention on the Law of Treaties, May 23, 1969, 1155 U.N.T.S. 331.
4. European Commission, High Seas Treaty Enters into Force: A Milestone for Ocean Conservation, OCEANS AND FISHERIES (Jan. 16, 2026), available at https://oceans-and-fisheries.ec.europa.eu/news/high-seas-treaty-enters-force-milestone-ocean conservation-2026-01-16_en (last visited Oct. 3, 2026).
5. Fietta LLP, The BBNJ Agreement Enters into Force, FIETTA LLP (2026), available at https://www.fiettalaw.com/pil_news/the-bbnj-agreement-enters-into-force/ (last visited Oct. 4, 2026).
6. International Institute for Sustainable Development, Earth Negotiations Bulletin: Daily Report for 28 February 2023, EARTH NEGOTIATIONS BULLETIN (2023), available at https://enb.iisd.org/marine-biodiversity-beyond-national-jurisdiction-bbnj-igc5-resumed-daily-report-28feb2023 (last visited Oct. 4, 2026).
7. China, Japan and Brazil Secure Sear at High Seas Treaty Talks, CLIMATE HOME NEWS (Jan. 2026), available at https://www.climatechangenews.com/2026/01/20/china-japan-secure-seat-bbnj-deep-sea-conservation-high-seas/ (last visited Oct. 5, 2026).