International waters are the areas shown in dark blue in this map, i.e. outside exclusive economic zones which are in light blue.

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.[1]

"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.[2] 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."[3] 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.[4]

The high seas make up 50% of the surface area of the planet and cover over two-thirds of the ocean.[5]

Ships sailing the high seas are generally under the jurisdiction of the flag state (if there is one);[6] however, when a ship is involved in certain criminal acts, such as piracy,[7] any nation can exercise jurisdiction under the doctrine of universal jurisdiction. International waters can be contrasted with internal waters, territorial waters and exclusive economic zones.

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.[8]

International waterways

The Río de la Plata basin gives sea access to landlocked Paraguay and Bolivia, and navigation is free for all international commercial ships.
Komárno in Slovakia is an inland port on the Danube River which is an important international waterway.

Several international treaties have established freedom of navigation on semi-enclosed seas.

Other international treaties have opened up rivers, which are not traditionally international waterways.

Disputes over international waters

See also: Territorial claims in the Arctic, South China Sea dispute, and Australian Antarctic Territory

The Atlantic Ocean has the busiest ocean trade routes in the world.

Current unresolved disputes over whether particular waters are "International waters" include:

International waters agreements

Limits of national jurisdiction and sovereignty
Outer space (including Earth orbits; the Moon and other celestial bodies, and their orbits)
national airspace territorial waters airspace contiguous zone airspace[citation needed] international airspace
land territory surface internal waters surface territorial waters surface contiguous zone surface Exclusive Economic Zone surface international waters surface[note 1]
internal waters territorial waters exclusive economic zone international waters[note 1]
land territory underground continental shelf surface extended continental shelf surface international seabed surface
continental shelf underground extended continental shelf underground international seabed underground
  full national jurisdiction and sovereignty
  restrictions on national jurisdiction and sovereignty
  international jurisdiction per common heritage of mankind

Global agreements

Regional agreements

Map showing the parties of the Barcelona Convention.

At least ten conventions are included within the Regional Seas Program of UNEP,[21] including:

  1. the Atlantic Coast of West and Central Africa[22]
  2. the North-East Pacific (Antigua Convention)
  3. the Mediterranean (Barcelona Convention)
  4. the wider Caribbean (Cartagena Convention)
  5. the South-East Pacific[23]
  6. the South Pacific (Nouméa Convention)
  7. the East African seaboard[24]
  8. the Kuwait region (Kuwait Convention)
  9. the Red Sea and the Gulf of Aden (Jeddah Convention)

Addressing regional freshwater issues is the 1992 Helsinki Convention on the Protection and Use of Transboundary Watercourses and International Lakes (UNECE/Helsinki Water Convention)[25]

Water-body-specific agreements

International waters institutions

Freshwater institutions

Marine institutions

Underground international waters

When an underground body of water transcends international boundaries, the term transboundary aquifer applies.

UNESCO has recognized the issue in several publications like Transboundary Aquifers, Challenges and the way forward.[30]

Another term referring to underground international waters is Transboundariness. It is a concept, a measure and an approach first introduced in 2017.[31] The relevance of this approach is that the physical features of the aquifers become just additional variables among the broad spectrum of considerations of the transboundary nature of an aquifer:

The discussion changes from the traditional question of "is the aquifer transboundary?" to "how transboundary is the aquifer?".

The socio-economic and political contexts effectively overwhelm the aquifer's physical features adding its corresponding geostrategic value (its transboundariness) [32]

The criteria proposed by this approach attempt to encapsulate and measure all potential variables that play a role in defining the transboundary nature of an aquifer and its multidimensional boundaries.[33]

See also

Explanatory notes

  1. ^ a b The 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.


  1. ^ International Waters Archived 27 January 2009 at the Wayback Machine, United Nations Development Programme
  2. ^ Buchanan, Michael. "Who's in charge here?". ShareAmerica. Retrieved 3 August 2020.
  3. ^ Text of CONVENTION ON THE HIGH SEAS Archived 22 February 2019 at the Wayback Machine (U.N.T.S. No. 6465, vol. 450, pp. 82–103)
  4. ^ "What is the EEZ". National Ocean Service. Retrieved 8 September 2019.
  5. ^ "THE HIGH SEAS". Ocean Unite. Archived from the original on 9 July 2021. Retrieved 7 January 2019.
  6. ^ UNCLOS article 92(1)
  7. ^ UNCLOS article 105
  8. ^ Jesper Jarl Fanø (2019). Enforcing International Maritime Legislation on Air Pollution through UNCLOS. Hart Publishing.
  9. ^ Law of the Sea Institute (1983). The Law of the Sea in the 1980s. University of Virginia: Law of the Sea Institute. pp. 600–619.
  10. ^ "Ordinance Governing the Admission of Foreign Warships and Military Aircraft to Danish Territory in Time of Peace" (PDF).
  11. ^ "Anordning om fremmede orlogsfartøjers og militære luftfartøjers adgang til dansk område under fredsforhold".
  12. ^ Carnaghan, Matthew; Goody, Allison (26 January 2006), Canadian Arctic Sovereignty, Library of Parliament, archived from the original on 2 December 2016, retrieved 16 December 2016
  13. ^ "International Freshwater Treaties Database". Archived from the original on 12 November 2011. Retrieved 8 November 2011.
  14. ^ "Yearbook of International Cooperation on Environment and Development". Archived from the original on 12 February 2009.
    Marine Environment
    Marine Living Resources
    Freshwater Resources
  15. ^ "International Maritime Organization". Archived from the original on 26 October 2008. Retrieved 1 April 2017.
  16. ^ "United Nations Convention on Law of the Sea". Retrieved 8 November 2011.
  17. ^ "CIW" (PDF). Retrieved 8 November 2011.
  18. ^ "Bellagio Draft" (PDF). Retrieved 8 November 2011.
  19. ^ "Text of Ramsar Convention and other key original documents". Archived from the original on 4 November 2011. Retrieved 8 November 2011.
  20. ^ Text of the Convention on Biological Diversity especially Articles 12–13, as related to transboundary aquatic ecosystems
  21. ^ "Regional Seas Program". Retrieved 8 November 2011.
  22. ^ "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)". Archived from the original on 9 January 2004. Retrieved 8 November 2011.
  23. ^ Lima Convention Archived 17 April 2019 at the Wayback Machine, 1986)
  24. ^ Nairobi Convention Archived 26 May 2013 at the Wayback Machine, 1985);
  25. ^ "Convention on the Protection and Use of Transboundary Watercourses and International Lakes". Retrieved 8 November 2011.
  26. ^ "Convention on the Protection of the Marine Environment of the Baltic Sea Area". Archived from the original on 28 September 2011. Retrieved 8 November 2011.
  27. ^ "Commission on the Protection of the Black Sea Against Pollution". Retrieved 1 April 2017.
  28. ^ Framework Convention for the Protection of the Marine Environment of the Caspian Sea, 2003
  29. ^ Convention for the Sustainable Management of Lake Tanganyika, 2003
  30. ^ "Transboundary Aquifers, Challenges and the way forward".
  31. ^ Sanchez, Rosario; Eckstein, Gabriel (July 2017). "Aquifers Shared Between Mexico and the United States: Management Perspectives and Their Transboundary Nature". Groundwater. 55 (4): 495–505. doi:10.1111/gwat.12533. PMID 28493280. S2CID 29936628.
  32. ^ Sanchez, Rosario (May 2018). "Transboundary Groundwater" (PDF). Water Resources Impact.
  33. ^ Copied content from aquifer; see that page's history for attribution