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Exclusive Economic Zones: What the 200-Nautical-Mile Rule Means

An exclusive economic zone can extend up to 200 nautical miles from a coastal baseline and gives the coastal state resource rights and specified jurisdiction, while other states retain navigation, overflight and cable-laying freedoms under the law of the sea.

Timeline

  1. 1982-12-10: The United Nations Convention on the Law of the Sea was opened for signature at Montego Bay.
  2. 1994-11-16: UNCLOS entered into force.
  3. Ongoing: Coastal states chart and, where coasts face one another, delimit maritime zones under international law.

An exclusive economic zone, or EEZ, is a maritime zone beyond and adjacent to a country’s territorial sea. Under Article 57 of the United Nations Convention on the Law of the Sea, it may extend no farther than 200 nautical miles from the baselines used to measure the territorial sea. Two hundred nautical miles equals about 370.4 kilometers, but “up to” matters because neighboring or opposite coasts can produce overlapping claims that require delimitation. [1][2][3]

Within the EEZ, the coastal state has sovereign rights to explore, exploit, conserve and manage living and nonliving natural resources in the waters, seabed and subsoil. Those rights cover matters such as fisheries, oil and gas, minerals, and energy from water, currents and wind. The state also has specified jurisdiction over artificial islands and installations, marine scientific research, and protection and preservation of the marine environment. [1][2]

An EEZ is not the same as territorial waters. A state exercises sovereignty over its territorial sea subject to rules such as innocent passage, while the EEZ uses a narrower resource-and-jurisdiction regime. UNCLOS Article 58 preserves for all states freedoms of navigation and overflight and the laying of submarine cables and pipelines, along with related lawful uses. Describing the entire EEZ as if it were national land or fully sovereign sea territory is therefore misleading. [1][2]

The distance is measured from a legal baseline, not simply from any visible point on a beach. NOAA explains that a normal baseline generally follows the low-water line shown on officially recognized large-scale charts. From that baseline, charts can depict a 12-nautical-mile territorial sea, a 24-nautical-mile contiguous zone and a 200-nautical-mile EEZ. Geography, islands and agreements with neighboring states can make real boundaries more complex than concentric bands. [3][4]

The continental shelf is related but legally distinct. EEZ rights cover resources in the water column as well as the seabed and subsoil, while continental-shelf rights concern the seabed and subsoil. Under UNCLOS, a continental shelf can in specified circumstances extend beyond 200 nautical miles if the coastal state establishes the outer limits under the convention’s criteria. That does not extend the EEZ’s water-column resource regime beyond its maximum distance. [2][4]

For the United States, NOAA says the EEZ extends no more than 200 nautical miles from the territorial-sea baseline and includes waters adjacent to the states and U.S. territories. NOAA charts the relevant maritime limits. The United States has not ratified UNCLOS, but NOAA states that it recognizes the 1982 convention as reflecting customary international law and complies with its provisions. Specific U.S. statutes can use related terms with tailored inner boundaries. [3][4]

The durable way to read an EEZ dispute is to separate three questions: where the lawful boundary lies, which activity is at issue, and which rights the law assigns to each state. Fishing, drilling, scientific research, navigation and cable laying do not all follow the same rule. Maps can show asserted lines without resolving their legal status, so current treaty text, agreements, adjudications and official charts are more reliable than treating a 200-mile circle as automatic sovereignty. [1][2][3][4]

Sources

  1. United Nations — UNCLOS Part V: Exclusive Economic Zone
  2. United Nations — UNCLOS official English text
  3. NOAA National Ocean Service — What is the EEZ?
  4. NOAA National Ocean Service — What is the law of the sea?

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