The United Nations Convention on the Law of the Sea (UNCLOS), established in 1982 and often referred to as the Law of the Sea, divides marine areas into five major zones. These zones are Internal Waters, Territorial Sea, Contiguous Zone, Exclusive Economic Zone (EEZ), and the High Seas. The convention is unique in providing a framework for state jurisdiction in maritime spaces. It sets a different legal status for each zone, providing the foundation for offshore governance by coastal states and those navigating the oceans.
Maritime Zones Baseline
The baseline of maritime zones is defined as the low-water line along the coast, as officially recognized by the coastal state.
Internal Waters
Internal waters refer to the waters on the landward side of the baseline from which the breadth of the territorial sea is measured. Each coastal state possesses full sovereignty over its internal waters just as it does over its land territory. Bays, ports, inlets, rivers, and even lakes connected to the sea are examples of internal waters. There is no right of innocent passage through these waters. The innocent passage refers to navigation that doesn’t threaten peace or security.
Territorial Sea
The territorial sea extends 12 nautical miles seaward from its baselines. A nautical mile, slightly more than a land-measured mile, is based on the Earth’s circumference and is equal to one minute of latitude. The rights of coastal states extend to the surface, seabed, subsoil, and airspace. However, these rights are limited by the principle of innocent passage.
Contiguous Zone
The contiguous zone extends 24 nautical miles from the baseline. This intermediary zone resides between the territorial sea and the high seas. Here, a coastal state can prevent and punish violation of its fiscal, immigration, sanitary, and customs laws within its territory and territorial sea. However, in contrast with the territorial sea, the rights only extend to the ocean’s surface and floor, not the airspace.
Exclusive Economic Zone
A coastal state may claim an Exclusive Economic Zone (EEZ) that extends up to 200 nautical miles from its baseline. Within its EEZ, a coastal state has sovereign rights for exploring, exploiting, conserving and managing natural resources of the seabed and subsoil. The state also has the right to produce energy from water, currents, and winds. The EEZ doesn’t confer the right to limit navigation or overflight except in limited instances.
| Marine Zone | Description |
|---|---|
| Internal Waters | Water bodies on the landward side of the baseline with complete sovereignty. |
| Territorial Sea | Extends up to 12 nautical miles seaward from the baseline. |
| Contiguous Zone | Stretches up to 24 nautical miles seaward from the baseline. |
| Exclusive Economic Zone | Beyond and adjacent to territorial sea, extends up to 200 nautical miles. |
High Seas
The term High Seas refers to the ocean surface and the water column beyond the EEZ. Considered as the common heritage of all mankind, the high seas are beyond any national jurisdiction. States can conduct activities in these zones, provided they are for peaceful purposes like transit, undersea exploration, and marine science.