United Nations Convention on the Law of the Sea (UNCLOS)

The United Nations Convention on the Law of the Sea (UNCLOS), also called the Law of the Sea Convention or the Law of the Sea treaty, is the international agreement that resulted from the third United Nations Conference on the Law of the Sea (UNCLOS III), which took place between 1973 and 1982.

The Law of the Sea Convention defines the rights and responsibilities of nations with respect to their use of the world’s oceans, establishing guidelines for businesses, the environment, and the management of marine natural resources.¬† UNCLOS came into force in 1994. As of June 2016, 167 countries and the European Union have joined in the Convention.

UNCLOS replaces the older ‘freedom of the seas’ concept, dating from the 17th century: national rights were limited to a specified belt of water extending from a nation’s coastlines, usually 3 nautical miles.

Limit of various areas set by UNCLOS III

The convention set the limit of various areas, measured from a carefully defined baseline. Normally, a sea baseline follows the low-water line, but when the coastline is deeply indented, has fringing islands or is highly unstable, straight baselines may be used. The areas are as follows:

Internal waters

Covers all water and waterways on the landward side of the baseline. The coastal state is free to set laws, regulate use, and use any resource. Foreign vessels have no right of passage within internal waters.

Territorial waters

Out to 12 nautical miles (22 kilometres) from the baseline, the coastal state is free to set laws, regulate use, and use any resource. Vessels were given the right of innocent passage through any territorial waters, with strategic straits allowing the passage of military craft as transit passage, in that naval vessels are allowed to maintain postures that would be illegal in territorial waters.

“Innocent passage” is defined by the convention as passing through waters in an expeditious and continuous manner, which is not “prejudicial to the peace, good order or the security” of the coastal state. Fishing, polluting, weapons practice, and spying are not “innocent”, and submarines and other underwater vehicles are required to navigate on the surface and to show their flag. Nations can also temporarily suspend innocent passage in specific areas of their territorial seas, if doing so is essential for the protection of their security.

Archipelagic waters

A baseline is drawn between the outermost points of the outermost islands, subject to these points being sufficiently close to one another. All waters inside this baseline are designated Archipelagic Waters. The state has sovereignty over these waters (like internal waters), but subject to existing rights including traditional fishing rights of immediately adjacent states. Foreign vessels have right of innocent passage through archipelagic waters (like territorial waters).

Contiguous zone

Beyond the 12-nautical-mile (22 km) limit, there is a further 12 nautical miles (22 km) from the territorial sea baseline limit, the contiguous zone, in which a state can continue to enforce laws in four specific areas: customs, taxation, immigration and pollution, if the infringement started within the state’s territory or territorial waters, or if this infringement is about to occur within the state’s territory or territorial waters. This makes the contiguous zone a hot pursuit area.

Exclusive economic zones (EEZs)

These extend 200 nautical miles (370 kilometres) from the baseline. Within this area, the coastal nation has sole exploitation rights over all natural resources. Foreign nations have the freedom of navigation and overflight, subject to the regulation of the coastal states. Foreign states may also lay submarine pipes and cables.

Continental shelf

The continental shelf is defined as the natural prolongation of the land territory to the continental margin’s outer edge, or 200 nautical miles (370 km) from the coastal state’s baseline, whichever is greater. A state’s continental shelf may exceed 200 nautical miles (370 km) until the natural prolongation ends. However, it may never exceed 350 nautical miles (650 kilometres) from the baseline. Coastal states have the right to harvest mineral and non-living material in the subsoil of its continental shelf, to the exclusion of others. Coastal states also have exclusive control over living resources “attached” to the continental shelf, but not to creatures living in the water column beyond the exclusive economic zone.

Other important provisions

Aside from its provisions defining ocean boundaries, the convention establishes general obligations for safeguarding the marine environment and protecting freedom of scientific research on the high seas, and also creates an innovative legal regime for controlling mineral resource exploitation in deep seabed areas beyond national jurisdiction, through an International Seabed Authority and the Common heritage of mankind principle.

Landlocked states are given a right of access to and from the sea, without taxation of traffic through transit states.