Definition

The sovereignty of a coastal State extends, beyond its land and territory and internal waters and, in the case of an archipelagic State, its archipelagic waters, to an adjacent belt of sea, described as the territorial sea. The breadth of its territorial sea must not exceed a limit of 12 nautical miles.

United Nations Convention on the Law of the Sea (UNCLOS) 1982, Articles 2 and 3 ¹