The United Nations Convention on the Law of the Sea (UNCLOS) is a comprehensive international treaty that establishes a legal framework for all marine and maritime activities, often called the "Constitution for the Oceans.". Its origin lies in the need to replace the older, fragmented "freedom of the seas" concept, which limited national rights to a narrow belt of water, with a unified regime to manage expanding maritime claims for resources and environmental protection. The Convention resulted from the Third United Nations Conference on the Law of the Sea (UNCLOS III), which took place between 1973 and 1982, and it replaced the four 1958 Geneva Conventions on the Law of the Sea. It was opened for signature on December 10, 1982, in Montego Bay, Jamaica, and entered into force on November 16, 1994.
The Convention, which comprises 320 articles and nine annexes, works by defining various maritime zones and the rights and duties of states within them. Key provisions include granting coastal states sovereignty over a Territorial Sea extending up to 12 nautical miles, where foreign vessels have the right of "innocent passage". It also establishes the Exclusive Economic Zone (EEZ), which extends up to 200 nautical miles from the baseline, where the coastal state has sovereign rights over natural resources and certain economic activities. UNCLOS also created three related institutions: the International Tribunal for the Law of the Sea (ITLOS) for dispute settlement, the International Seabed Authority (ISA) to regulate deep seabed mining, and the Commission on the Limits of the Continental Shelf (CLCS). While the Convention itself has never been formally amended using its cumbersome procedures, it has been supplemented by implementing agreements. The Agreement relating to the implementation of Part XI was signed in 1994, and more recently, the Agreement on the Conservation and Sustainable Use of Marine Biological Diversity of Areas beyond National Jurisdiction (BBNJ Agreement) was adopted in 2023 to protect ocean life in international waters.