Guide to marine areas according to the UN Convention on the Law of the Sea

Chris Simoens
04 August 2017
The UN Convention defines specific marine areas. What do they mean?
Ocean zones



  • The line which demarcates the boundary between land and sea (= low water line).

Inland water

  • Water on the inland side of the baseline (for example, estuaries).

Territorial waters

  • Up to 12 nautical miles from the baseline (1 nautical mile = 1852 metres).
  • Littoral states have full sovereignty here. In principle, ships under the flag of other states are entitled to innocent passage.

Contiguous zone

  • Between 12 and 24 nautical miles from the baseline.
  • Littoral states can take action here if their laws are violated (customs, taxes, immigration, etc.). They can also inspect and sanction the traffic of archaeological artefacts from the sea in this area.

Exclusive Economic Zone (EEZ)

  • Up to 200 nautical miles from the baseline.
  • Littoral states have the sovereign right to economically exploit these zones, for example to fish or generate energy from water, currents and wind. They are also responsible for the protection of the marine environment.

Continental shelf

  • Similar to an EEZ, but including the sea bed. The continental shelf runs until the continental slope. It sometimes extends further than 200 nautical miles.
  • Littoral states have similar exclusive rights as in the EEZ, and they can also carry out drilling, and lay cables and pipelines.

High sea and the Area

  • The seas beyond the continental shelf. The high sea covers the water column and the Area covers the sea bed.
  • Here, freedom of navigation and fishing, etc., applies. The states under whose flag a ship sails bear full responsibility for that ship. Each state must take account of the interests of other states. The high sea is uniquely devoted to peaceful purposes.

The freedom to fish is limited by the obligation to manage straddling fish stocks optimally, as stipulated in the Fish Stock Agreement of 1995. All states have the obligation to protect the marine environment, pollution of seawater and the sea bed is therefore not permitted. Reference is made to the Common Heritage of Mankind: states and companies must conserve our common heritage for future generations. The exploitation of minerals from the sea bed falls under this stipulation.

International waters

  • Besides the high sea, these include the sea bed beyond 200 nautical miles, in other words beyond the Exclusive Economic Zone.
Law of the sea
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