“International waters” is not a defined term in international law. It is an informal term, which most often refers to waters beyond the "territorial sea" of any state. In other words, "international waters" is often used as an informal synonym for the more formal term high seas or, in Latin, mare liberum (meaning free sea).
International waters (high seas) do not belong to any State's jurisdiction, known under the doctrine of 'Mare liberum'. 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 200 nautical miles (230 mi; 370 km) 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.
UNCLOS also contains, in its part XII, special provisions for the protection of the marine environment, which, in certain cases, allow port States to exercise extraterritorial jurisdiction over foreign ships on the high seas if they violate international environmental rules (adopted by the IMO), such as the MARPOL Convention.
The Southern Ocean: Australia claims an exclusive economic zone (EEZ) around its Antarctic territorial claim. Since this claim is only recognised by four other countries, the EEZ claim is also disputed.
Area around Okinotorishima: Japan claims Okinotorishima is an islet and thus they should have an EEZ around it, but some[quantify] neighboring countries claim it is an atoll and thus should not have an EEZ.
South China Sea: See Territorial disputes in the South China Sea. Some countries[note 1] consider (at least part of) the South China Sea as international waters, but this viewpoint is not universal. Notably, China, which opposes any suggestion that coastal States could be obliged to share the resources of the exclusive economic zone with other powers that had historically fished there, claims historical rights to the resources of the exclusive economic zones of all other coastal States in the South China Sea.
In addition to formal disputes, the government of Somalia exercises little control de facto over Somali territorial waters. Consequently, much piracy, illegal dumping of waste and fishing without permit has occurred.
Although water is often seen as a source of conflict, recent research suggests that water management can be a source for cooperation between countries. Such cooperation will benefit participating countries by being the catalyst for larger socio-economic development. For instance, the countries of the Senegal River Basin that cooperate through the Organisation pour la Mise en Valeur du Fleuve Sénégal (OMVS) have achieved greater socio-economic development and overcome challenges relating to agriculture and other issues.
^Including Japan, India, the United States, an arbitral tribunal constituted under Annex VII to the 1982 United Nations Convention on Law of the Sea, and the People's Republic of China, which opposed any suggestion that coastal States could be obliged to share the resources of the exclusive economic zone with other powers that had historically fished in those waters during the Third Conference of the United Nations on the Law of the Seas.
^ abThe term "international waters" technically includes the "Contiguous Zone" and "Exclusive Economic Zone," although the chart only uses this term where no national jurisdiction or special rights apply.
^International Waters Archived 27 January 2009 at the Wayback Machine, United Nations Development Programme
^Buchanan, Michael. "Who's in charge here?". ShareAmerica. Retrieved 3 August 2020.
^Text of CONVENTION ON THE HIGH SEAS (U.N.T.S. No. 6465, vol. 450, pp. 82–103)
^"What is the EEZ". National Ocean Service. Retrieved 8 September 2019.
^"THE HIGH SEAS". Ocean Unite. Retrieved 7 January 2019.
^"Bellagio Draft" (PDF). Retrieved 8 November 2011.
^"Text of Ramsar Convention and other key original documents". Ramsar.org. Archived from the original on 4 November 2011. Retrieved 8 November 2011.
^Text of the Convention on Biological Diversity especially Articles 12–13, as related to transboundary aquatic ecosystems
^"Regional Seas Program". Unep.org. Retrieved 8 November 2011.
^"Convention for Co-operation in the Protection and Development of the Marine and Coastal Environment of the West and Central African Region; and Protocol (1981)". Sedac.ciesin.org. Retrieved 8 November 2011.