The United Nations Convention on the Law of the Sea (UNCLOS) is the principal multilateral framework governing the rights and responsibilities of states in their use of the world's oceans. It was opened for signature in Montego Bay, Jamaica on 10 December 1982 and entered into force on 16 November 1994, one year after the 60th ratification. UNCLOS is sometimes called the "constitution for the oceans."
The Convention codifies and develops customary law across several maritime zones measured from a state's baselines:
- Territorial sea up to 12 nautical miles, where the coastal state exercises sovereignty subject to innocent passage.
- Contiguous zone up to 24 nm, for enforcement of customs, immigration, fiscal, and sanitary laws.
- Exclusive Economic Zone (EEZ) up to 200 nm, granting sovereign rights over living and non-living resources.
- Continental shelf, extending to 200 nm or beyond if natural prolongation is established before the Commission on the Limits of the Continental Shelf (CLCS).
- High seas and the Area (the seabed beyond national jurisdiction), designated as the "common heritage of mankind" and administered by the International Seabed Authority (ISA), headquartered in Kingston, Jamaica.
UNCLOS also establishes navigational regimes including transit passage through straits used for international navigation and archipelagic sea lanes passage. Part XV provides compulsory dispute settlement, with options including the International Tribunal for the Law of the Sea (ITLOS) in Hamburg, the International Court of Justice, or arbitration under Annex VII.
The 1994 Implementation Agreement modified Part XI (deep seabed mining) to address concerns of industrialised states, paving the way for broader ratification. A separate 1995 Agreement covers straddling and highly migratory fish stocks. In June 2023, states adopted the BBNJ Agreement on biodiversity beyond national jurisdiction as a further implementing instrument.
The United States has signed the 1994 Agreement but has not ratified UNCLOS, though it treats most provisions as reflecting customary international law.
Example
In the 2016 South China Sea Arbitration, an Annex VII tribunal constituted under UNCLOS ruled in favour of the Philippines against China's "nine-dash line" claims.
Frequently asked questions
No. The US signed the 1994 Implementation Agreement but the Senate has not given advice and consent to ratification. Washington nonetheless treats most navigational provisions as customary international law.
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