Territorial waters are areas of the ocean where a nation has sovereign rights. These rights include control of fishing, navigation, and shipping, as well as the use of the ocean’s natural resources.
The territorial waters of a nation include its internal waters and its territorial sea. Internal waters include lakes, rivers, and the waters within such coastal areas as bays and gulfs. A country’s territorial sea lies beyond its coast or the boundary of its internal waters. Nations have more authority over their internal waters than they have over their territorial seas. The main difference is that ships of other countries can freely cross territorial seas in peacetime.
Various nations have set different outer limits for their territorial sea. A United Nations-sponsored treaty called the Law of the Sea Convention, which took effect in 1994, provides for a territorial sea of 12 nautical miles. A nautical mile equals about 1.2 statute miles or 1.9 kilometers. Most of the approximately 120 coastal nations, including the United States, observe the 12-mile limit. A few nations claim as much as 200 nautical miles. Many countries prohibit foreigners from fishing in their territorial sea. Many nations also claim exclusive fishing and other rights in an exclusive economic zone, which extends 200 nautical miles from shore.