China deposited with UN Secretary-General Antonio Guterres on December 15 an instrument of ratification of 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, according to documents published on the official website of the United Nations on Tuesday.

The agreement is an important international treaty under the UN framework. Based on the United Nations Convention on the Law of the Sea, it aims to conserve and sustainably use marine biological diversity, focusing on deep-sea genetic resources, marine protected areas, environmental impact assessments and capacity building. It has further established legal norms for deep-sea and open-sea activities of all countries, profoundly influencing the international maritime order.

The negotiation process for the agreement began in 2004. The agreement was adopted by consensus on June 19, 2023, and opened for signature on September 20 of the same year. To date, 144 countries and the European Union (EU) have signed the agreement, and 80 countries and the EU have deposited instruments of ratification, approval, acceptance, or accession. The agreement will enter into force on January 17, 2026.

China participated in the entire negotiation process of the agreement and signed it on the first day it was opened for signature. On October 28, 2025, the 18th session of the Standing Committee of the 14th National People's Congress adopted a decision to ratify the agreement. China will become a contracting party from the date the agreement enters into force.

The agreement was reached after 19 years of negotiations involving more than 190 countries. When the agreement reached the required threshold of ratifications for entry into force, Guterres welcomed the development, calling it a "historic achievement for the ocean and for multilateralism."