Overview
The terms international waters or transboundary waters apply where any of the following types of bodies of water (or their drainage basins) transcend international boundaries: oceans, large marine ecosystems, enclosed or semi-enclosed regional seas and estuaries, rivers, lakes, groundwater systems (aquifers), and wetlands.
"International waters" is not a defined term in international law. It is an informal term, which sometimes refers to waters beyond the "territorial sea" of any country. In other words, "international waters" is sometimes used as an informal synonym for the more formal term "high seas", which under the doctrine of mare liberum (Latin for "freedom of the seas"), do not belong to any state's jurisdiction. As such, states have the right to fishing, navigation, overflight, laying cables and pipelines, as well as scientific research.
The Convention on the High Seas, signed in 1958, which has 63 signatories, defined "high seas" to mean "all parts of the sea that are not included in the territorial sea or in the internal waters of a State" and where "no State may validly purport to
subject any part of them to its sovereignty." The Convention on the High Seas was used as a foundation for the United Nations Convention on the Law of the Sea (UNCLOS), signed in 1982, which recognized exclusive economic zones extending from the baseline, where coastal states have sovereign rights to the water column and sea floor as well as the natural resources found there.
The high seas make up 50% of the surface area of the planet and cover over two-thirds of the ocean.
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