High Seas Treaty

The 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 or BBNJ Agreement, commonly known as the High Seas Treaty, is a legally binding instrument for the conservation and sustainable use of marine biological diversity of areas beyond national jurisdiction. It is an agreement under the United Nations Convention on the Law of the Sea (UNCLOS). The text was finalised during an intergovernmental conference at the UN on 4 March 2023 and adopted on 19 June 2023. On 19 September 2025, Morocco became the 60th country to ratify the agreement, setting the stage for its entry into force in January 2026.

In 2017, the United Nations General Assembly (UNGA) voted to convene an intergovernmental conference (IGC) to consider establishing an international legally binding instrument (ILBI) on the conservation and sustainable use of marine biodiversity beyond national jurisdiction (BBNJ). This was considered necessary because UNCLOS did not provide a framework for areas beyond national jurisdiction. There was a particular concern for marine biodiversity and the impact of overfishing on global fish stocks and ecosystem stability.

The treaty addresses four themes: (1) marine genetic resources (MGRs) and their digital sequence information, including the fair and equitable sharing of benefits; (2) area-based management tools (ABMTs), including marine protected areas (MPAs); (3) environmental impact assessments (EIAs); and (4) capacity building and transfer of marine technology (CB&TMT). The area-based management tools and environmental impact assessments relate mainly to conservation and sustainable use of marine biodiversity, while the marine genetic resources and capacity building and transfer of marine technology include issues of economic justice and equity.

Greenpeace called it "the biggest conservation victory ever". The main achievement is the new possibility to create marine protected areas in international waters. By doing so the agreement now makes it possible to protect 30% of the oceans by 2030 (part of the 30 by 30 target). Though the agreement does not directly address climate change, it also serves as a step towards protecting the ecosystems that store carbon in sediments.

The High Seas Treaty has 76 articles and two annexes. One of its main aims is "to act as stewards of the ocean in areas beyond national jurisdiction on behalf of present and future generations by protecting, caring for and ensuring responsible use of the marine environment, maintaining the integrity of ocean ecosystems and conserving the inherent value of biological diversity of areas beyond national jurisdiction". The Agreement recognizes traditional knowledge. It has articles regarding the "polluter-pays" principle, and different impacts of human activities including areas beyond the national jurisdiction of the countries making those activities. The agreement was adopted by the 193 United Nations Member States.

Both states and regional economic integration organizations can become parties to the Agreement. Before entering into force, the treaty needed to be ratified by at least 60 UN member states. The former treaty, UNCLOS, was adopted in 1982 and entered into force in 1994. As of October 2024, UNCLOS has 170 parties. The European Union pledged financial support for the process of ratification and implementation of the treaty.