
The terms international waters or transboundary waters apply where any of the following types of bodies of water (or their
drainage basin
A drainage basin is an area of land in which all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, ...
s) transcend international boundaries: oceans,
large marine ecosystems, enclosed or semi-enclosed regional seas and
estuaries
An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environm ...
, rivers, lakes,
groundwater
Groundwater is the water present beneath Earth's surface in rock and Pore space in soil, soil pore spaces and in the fractures of stratum, rock formations. About 30 percent of all readily available fresh water in the world is groundwater. A unit ...
systems (
aquifer
An aquifer is an underground layer of water-bearing material, consisting of permeability (Earth sciences), permeable or fractured rock, or of unconsolidated materials (gravel, sand, or silt). Aquifers vary greatly in their characteristics. The s ...
s), and
wetland
A wetland is a distinct semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially ...
s.
"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
Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...
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
The United Nations Convention on the Law of the Sea (UNCLOS), also called the Law of the Sea Convention or the Law of the Sea Treaty, is an international treaty that establishes a legal framework for all marine and maritime activities. , 169 sov ...
(UNCLOS), signed in 1982, which recognized
exclusive economic zone
An exclusive economic zone (EEZ), as prescribed by the 1982 United Nations Convention on the Law of the Sea, is an area of the sea in which a sovereign state has exclusive rights regarding the exploration and use of marine natural resource, reso ...
s 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.
Ships sailing the high seas are generally under the jurisdiction of the
flag state (if there is one); however, when a ship is involved in certain criminal acts, such as
piracy
Piracy is an act of robbery or criminal violence by ship or boat-borne attackers upon another ship or a coastal area, typically with the goal of stealing cargo and valuable goods, or taking hostages. Those who conduct acts of piracy are call ...
, any nation can exercise jurisdiction under the doctrine of
universal jurisdiction
Universal jurisdiction is a legal principle that allows Sovereign state, states or International organization, international organizations to prosecute individuals for serious crimes, such as genocide, War crime, war crimes, and crimes against hu ...
. 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.
Underground Transboundary Waters
When an underground water crosses international boundaries, the term transboundary aquifer applies. The term transboundariness can then be applied, which is a concept, measure and approach first introduced in 2017 when talking about underground transboundary waters.
The importance of this approach is that the physical properties of aquifers become merely additional variables within the broad spectrum of the transboundary nature of an aquifer: social (population); economic (groundwater efficiency); political (cross-border); existing research or data; water quality and quantity; other issues that drive the agenda (security, trade, immigration, etc.).
The criteria proposed through this approach attempt to encompass and quantify all potential variables that play a role in defining the transboundary nature and multidimensional boundaries of an underground transboundary water.
International waterways

Several international treaties have established
freedom of navigation on semi-enclosed seas.
* The
Copenhagen Convention of 1857 opened access to the
Baltic Sea
The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by the countries of Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden, and the North European Plain, North and Central European Plain regions. It is the ...
by abolishing the
Sound Dues and making the
Danish straits an international waterway free to all commercial shipping. Separately, the Royal Ordinance of 1999 regulates the access of foreign warships to Danish waters.
* Several conventions have opened the
Bosphorus and
Dardanelles
The Dardanelles ( ; ; ), also known as the Strait of Gallipoli (after the Gallipoli peninsula) and in classical antiquity as the Hellespont ( ; ), is a narrow, natural strait and internationally significant waterway in northwestern Turkey th ...
to shipping. The latest, the
, maintains the straits' status as an international waterway.
Other international treaties have opened up rivers, which are not traditionally international waterways.
* The
Río de la Plata basin, including the rivers
Paraná,
Uruguay
Uruguay, officially the Oriental Republic of Uruguay, is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast, while bordering the Río de la Plata to the south and the A ...
and
Paraguay
Paraguay, officially the Republic of Paraguay, is a landlocked country in South America. It is bordered by Argentina to the Argentina–Paraguay border, south and southwest, Brazil to the Brazil–Paraguay border, east and northeast, and Boli ...
, is legally open for all international commercial ships without restriction, it notably gives sea access to landlocked
Paraguay
Paraguay, officially the Republic of Paraguay, is a landlocked country in South America. It is bordered by Argentina to the Argentina–Paraguay border, south and southwest, Brazil to the Brazil–Paraguay border, east and northeast, and Boli ...
and
Bolivia
Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...
.
* The
Danube River is an international waterway so that
Germany
Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...
and
Croatia
Croatia, officially the Republic of Croatia, is a country in Central Europe, Central and Southeast Europe, on the coast of the Adriatic Sea. It borders Slovenia to the northwest, Hungary to the northeast, Serbia to the east, Bosnia and Herze ...
, as well as landlocked
Austria
Austria, formally the Republic of Austria, is a landlocked country in Central Europe, lying in the Eastern Alps. It is a federation of nine Federal states of Austria, states, of which the capital Vienna is the List of largest cities in Aust ...
,
Slovakia
Slovakia, officially the Slovak Republic, is a landlocked country in Central Europe. It is bordered by Poland to the north, Ukraine to the east, Hungary to the south, Austria to the west, and the Czech Republic to the northwest. Slovakia's m ...
,
Hungary
Hungary is a landlocked country in Central Europe. Spanning much of the Pannonian Basin, Carpathian Basin, it is bordered by Slovakia to the north, Ukraine to the northeast, Romania to the east and southeast, Serbia to the south, Croatia and ...
,
Serbia
, image_flag = Flag of Serbia.svg
, national_motto =
, image_coat = Coat of arms of Serbia.svg
, national_anthem = ()
, image_map =
, map_caption = Location of Serbia (gree ...
and
Moldova
Moldova, officially the Republic of Moldova, is a Landlocked country, landlocked country in Eastern Europe, with an area of and population of 2.42 million. Moldova is bordered by Romania to the west and Ukraine to the north, east, and south. ...
can have secure access to the
Black Sea
The Black Sea is a marginal sea, marginal Mediterranean sea (oceanography), mediterranean sea lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bound ...
.
Disputes over international waters

Current unresolved disputes over whether particular waters are "International waters" include:
*
Arctic Ocean
The Arctic Ocean is the smallest and shallowest of the world's five oceanic divisions. It spans an area of approximately and is the coldest of the world's oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, ...
: While Canada, Denmark, Russia and Norway all regard parts of the Arctic seas as ''national waters'' or ''
internal waters'', most
European Union
The European Union (EU) is a supranational union, supranational political union, political and economic union of Member state of the European Union, member states that are Geography of the European Union, located primarily in Europe. The u ...
countries and the United States officially regard the whole region as international waters. The
Northwest Passage through the
Arctic Archipelago is one of the more prominent examples, with Canada claiming it as
internal waters, while the United States and the European Union considers it an
international strait.
*
Southern Ocean
The Southern Ocean, also known as the Antarctic Ocean, comprises the southernmost waters of the world ocean, generally taken to be south of 60th parallel south, 60° S latitude and encircling Antarctica. With a size of , it is the seco ...
: Australian claim to an
exclusive economic zone
An exclusive economic zone (EEZ), as prescribed by the 1982 United Nations Convention on the Law of the Sea, is an area of the sea in which a sovereign state has exclusive rights regarding the exploration and use of marine natural resource, reso ...
(EEZ) in Antarctica is challenged by Japan.
*
Okinotorishima: Japanese claim to an EEZ around Okinotorishima is challenged by China, South Korea, and Taiwan.
*
South China Sea
The South China Sea is a marginal sea of the Western Pacific Ocean. It is bounded in the north by South China, in the west by the Indochinese Peninsula, in the east by the islands of Taiwan island, Taiwan and northwestern Philippines (mainly Luz ...
: Disputes exist between Brunei, China, Indonesia, Malaysia, the Philippines, Taiwan, and Vietnam.
International waters agreements
Global agreements
* International Freshwater Treaties Database (freshwater only).
* The Yearbook of International Cooperation on Environment and Development profiles agreements regarding the Marine Environment, Marine Living Resources and Freshwater Resources.
* 1972 London
Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter (London Convention 1972).
* 1973 London
International Convention for the Prevention of Pollution from Ships, 1973
MARPOL
* 1982
United Nations Convention on Law of the Sea (United Nations Convention on Law of the Sea, ''United Nations''; especially parts XII–XIV).
* 1997
United Nations Convention on the Law of Non-Navigational Uses of International Watercourses (CIW) – ''not ratified''.
* Transboundary Groundwater Treaty, Bellagio Draft – proposed, but ''not signed''.
* Other global conventions and treaties with implications for International Waters:
** 1971
Ramsar Convention
The Ramsar Convention on Wetlands of International Importance Especially as Waterfowl Habitat is an international treaty for the conservation and sustainable use of Ramsar site, Ramsar sites (wetlands). It is also known as the Convention on We ...
on Wetlands.
** 1992
Convention on Biological Diversity.
** 2023
High Seas Treaty (BBNJ Agreement)
Regional agreements

At least ten conventions are included within the Regional Seas Program of
UNEP
The United Nations Environment Programme (UNEP) is responsible for coordinating responses to environmental issues within the United Nations system. It was established by Maurice Strong, its first director, after the Declaration of the United Nati ...
, including:
# the
Atlantic Coast of
West and Central Africa
# the North-East Pacific (Antigua Convention)
# the
Mediterranean
The Mediterranean Sea ( ) is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean basin and almost completely enclosed by land: on the east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern ...
(
Barcelona Convention)
# the wider
Caribbean
The Caribbean ( , ; ; ; ) is a region in the middle of the Americas centered around the Caribbean Sea in the Atlantic Ocean, North Atlantic Ocean, mostly overlapping with the West Indies. Bordered by North America to the north, Central America ...
(Cartagena Convention)
# the South-East Pacific
# the
South Pacific (Nouméa Convention)
# the East African seaboard
# the Kuwait region (Kuwait Convention)
# the
Red Sea
The Red Sea is a sea inlet of the Indian Ocean, lying between Africa and Asia. Its connection to the ocean is in the south, through the Bab-el-Mandeb Strait and the Gulf of Aden. To its north lie the Sinai Peninsula, the Gulf of Aqaba, and th ...
and the
Gulf of Aden
The Gulf of Aden (; ) is a deepwater gulf of the Indian Ocean between Yemen to the north, the Arabian Sea to the east, Djibouti to the west, and the Guardafui Channel, the Socotra Archipelago, Puntland in Somalia and Somaliland to the south. ...
(Jeddah Convention)
Addressing regional freshwater issues is the 1992
Helsinki
Helsinki () is the Capital city, capital and most populous List of cities and towns in Finland, city in Finland. It is on the shore of the Gulf of Finland and is the seat of southern Finland's Uusimaa region. About people live in the municipali ...
Convention on the Protection and Use of Transboundary Watercourses and International Lakes (
UNECE
The United Nations Economic Commission for Europe (ECE or UNECE) is an intergovernmental organization or a specialized body of the United Nations. The UNECE is one of five regional commissions under the jurisdiction of the United Nations Econ ...
/Helsinki Water Convention)
Water-body-specific agreements
*
Baltic Sea
The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by the countries of Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden, and the North European Plain, North and Central European Plain regions. It is the ...
(
Helsinki Convention on the Protection of the Marine Environment of the Baltic Sea Area, 1992)
*
Black Sea
The Black Sea is a marginal sea, marginal Mediterranean sea (oceanography), mediterranean sea lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bound ...
(
Bucharest Convention)
*
Caspian Sea
The Caspian Sea is the world's largest inland body of water, described as the List of lakes by area, world's largest lake and usually referred to as a full-fledged sea. An endorheic basin, it lies between Europe and Asia: east of the Caucasus, ...
(
)
*
Lake Tanganyika (Convention for the Sustainable Management of Lake Tanganyika)
Convention for the Sustainable Management of Lake Tanganyika
2003
International waters institutions
Freshwater institutions
* The UNESCO
The United Nations Educational, Scientific and Cultural Organization (UNESCO ) is a List of specialized agencies of the United Nations, specialized agency of the United Nations (UN) with the aim of promoting world peace and International secur ...
International Hydrological Programme (IHP)
* The International Joint Commission between Canada and United States (IJC-CMI)
* The International Network of Basin Organizations (INBO)
* The International Shared Aquifer Resource Management project
* The International Water Boundary Commission (US Section) between Mexico and United States
* The International Water Management Institute (IWMI)
* The IUCN
The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...
Water and Nature Initiative (WANI)
* The Central Commission for the Navigation of the Rhine (CCNR)
Marine institutions
* The International Maritime Organization
The International Maritime Organization (IMO; ; ) is a List of specialized agencies of the United Nations, specialized agency of the United Nations responsible for regulating maritime transport. The IMO was established following agreement at a ...
(IMO)
* The International Seabed Authority
* The International Whaling Commission
The International Whaling Commission (IWC) is a specialised regional fishery management organisation, established under the terms of the 1946 International Convention for the Regulation of Whaling (ICRW) to "provide for the proper conservation ...
* The UNEP
The United Nations Environment Programme (UNEP) is responsible for coordinating responses to environmental issues within the United Nations system. It was established by Maurice Strong, its first director, after the Declaration of the United Nati ...
br>Regional Seas Programme
* The UNESCO
The United Nations Educational, Scientific and Cultural Organization (UNESCO ) is a List of specialized agencies of the United Nations, specialized agency of the United Nations (UN) with the aim of promoting world peace and International secur ...
Intergovernmental Oceanographic Commission (IOC)
* Th
International Ocean Institute
* The IUCN
The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...
Global Marine and Polar Programme (GMPP)
See also
* Baseline
* Birth aboard aircraft and ships
* Continental shelf
* Duty-free shop
* Extraterritoriality
In international law, extraterritoriality or exterritoriality is the state of being exempted from the jurisdiction of local law, usually as the result of diplomatic negotiations.
Historically, this primarily applied to individuals, as jurisdict ...
* Extraterritorial jurisdiction
Extraterritorial jurisdiction (ETJ) is the legal ability of a government to exercise authority beyond its normal boundaries.
Any authority can claim ETJ over any external territory they wish. However, for the claim to be effective in the external ...
* Extraterritorial operation
* Freedom of the seas
* Hugo Grotius
* International zone
* Ocean colonization
* Overfishing
Overfishing is the removal of a species of fish (i.e. fishing) from a body of water at a rate greater than that the species can replenish its population naturally (i.e. the overexploitation of the fishery's existing Fish stocks, fish stock), resu ...
* Seasteading
Explanatory notes
References
External links
Bibliography on Water Resources and International Law
Peace Palace Library
* The GEFbr>International Waters Resource Centre
(GEF IWRC)
* The Integrated Management of Transboundary Waters in Europe
TransCat
* Th
International Water Law Project
* Th
International Water Resources Association
(IWRA)
* Food and Agriculture Organization
The Food and Agriculture Organization of the United Nations; . (FAO) is a specialized agency of the United Nations that leads international efforts to defeat hunger and improve nutrition and food security. Its Latin motto, , translates ...
*
Ocean Atlas
*
Transboundary Marine Protected Areas
(MPAs) article
*
OneFish
fisheries research portal
*
of the World portal
*
Fishing Zeal
* The UNDP
The United Nations Development Programme (UNDP) is a United Nations agency tasked with helping countries eliminate poverty and achieve sustainable economic growth and human development. The UNDP emphasizes on developing local capacity towar ...
- GEFbr>article describing international waters
from which this article has been adapted.
* UNEP
The United Nations Environment Programme (UNEP) is responsible for coordinating responses to environmental issues within the United Nations system. It was established by Maurice Strong, its first director, after the Declaration of the United Nati ...
freshwater thematic portal o
transboundary waters
* UNESCO
The United Nations Educational, Scientific and Cultural Organization (UNESCO ) is a List of specialized agencies of the United Nations, specialized agency of the United Nations (UN) with the aim of promoting world peace and International secur ...
thematic portals fo
oceans
water
coasts and small islands
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