Argentina possesses 4,989 kilometers of Atlantic coastline extending from the Río de la Plata estuary in the north to Tierra del Fuego in the south. The coastline includes the provinces of Buenos Aires, Río Negro, Chubut, Santa Cruz, and Tierra del Fuego. The continental shelf off Argentina's coast is one of the widest in the world, extending up to 550 kilometers offshore in some areas, creating nutrient-rich feeding grounds that support commercial fisheries and marine mammal populations.
The Río de la Plata forms the second-largest river basin in South America after the Amazon, draining approximately 3.2 million square kilometers. The estuary itself measures 290 kilometers long and widens from 2 kilometers at its origin to 220 kilometers at its mouth where it meets the Atlantic Ocean. The Río de la Plata receives water primarily from the Paraná and Uruguay rivers. The sediment load from these rivers gives the water its characteristic brown color, carrying approximately 160 million tons of sediment annually into the estuary. The city of Buenos Aires sits on the western shore of the Río de la Plata, and the port infrastructure handles approximately 70 percent of Argentina's foreign trade by volume.
The Paraná River is the second-longest river in South America at 4,880 kilometers, forming part of Argentina's northern border with Paraguay and flowing southward through Argentine territory before joining the Río de la Plata. The river's width varies from 500 meters in its upper reaches to 50 kilometers in the delta region north of Buenos Aires. The Paraná Delta covers approximately 14,000 square kilometers of wetlands and islands where the river branches into multiple channels before reaching the Río de la Plata. The Yacyretá Dam, completed in 1994 on the border between Argentina and Paraguay near the city of Posadas, has a reservoir covering 1,600 square kilometers and installed capacity of 3,100 megawatts. Commercial shipping on the Paraná reaches upstream to the cities of Rosario and Santa Fe, which handle grain exports from the Pampas agricultural region.
The Argentine coast along the Atlantic Ocean exhibits minimal tidal range in the north near Buenos Aires, approximately 1 meter, increasing to over 9 meters in some southern coastal areas near the Valdés Peninsula. The coastline includes extensive sandy beaches along Buenos Aires Province, particularly near Mar del Plata, Argentina's largest beach resort city with a permanent population of 614,000 that expands significantly during the January and February summer season. Mar del Plata's Port, established in 1922, operates as Argentina's primary fishing port, with commercial fishing fleets targeting Argentine hake, red shrimp, and squid.
The Valdés Peninsula in Chubut Province extends approximately 100 kilometers into the Atlantic Ocean, creating two large gulfs: Golfo Nuevo to the south and Golfo San José to the north. The peninsula sits at 42 degrees south latitude and reaches a maximum elevation of 34 meters above sea level, though portions of the peninsula lie 42 meters below sea level, making these areas the lowest point in South America. UNESCO designated Península Valdés as a World Heritage Site in 1999 due to marine mammal concentrations. Southern right whales migrate to the sheltered waters of Golfo Nuevo and Golfo San José between June and December, with peak numbers in September and October. The protected waters around the peninsula host breeding populations estimated at over 2,000 individuals during peak season. Researchers have continuously monitored the right whale population since Roger Payne established a research station in the 1970s.
The peninsula's Punta Norte area hosts a breeding colony of Southern elephant seals that peaks at approximately 40,000 individuals in October. Adult male elephant seals can reach 4,000 kilograms and 5 meters in length. Orcas conduct intentional beach-grounding attacks on seal pups at Punta Norte during the February-April period, hunting in the shallow waters during high tide. Marine biologists have documented this specialized hunting behavior since the 1970s, identifying individual orcas that return to the same beaches across multiple years.
Puerto Madryn, a city of approximately 93,000 people on the Golfo Nuevo, serves as the gateway to Península Valdés and operates whale-watching tourism from June through December. The city's port handles aluminum exports from the Aluar plant, South America's only primary aluminum smelter, which has operated in Puerto Madryn since 1974 with annual production capacity of 460,000 tons. The port also supports offshore oil exploration activities in the San Jorge Gulf basin.
The southern Argentine coast includes the San Jorge Gulf, a deep-water embayment covering approximately 40,000 square kilometers between Chubut and Santa Cruz provinces. The gulf contains significant offshore oil and gas deposits that have been under development since the 1990s. The coastal cities of Comodoro Rivadavia in Chubut Province and Caleta Olivia in Santa Cruz Province serve as operational bases for petroleum extraction. Comodoro Rivadavia, with a population of approximately 182,000, became Argentina's first oil-producing center after drilling operations discovered petroleum in 1907.
The Beagle Channel forms a navigable waterway approximately 240 kilometers long and 5 kilometers wide at its narrowest point, separating the main island of Tierra del Fuego from smaller southern islands. The channel connects the Pacific and Atlantic oceans and represents the southernmost navigable route used by commercial vessels avoiding the Drake Passage. The city of Ushuaia, located on the northern shore of the Beagle Channel at 54.8 degrees south latitude, holds the designation of the world's southernmost city with a permanent population exceeding 56,000 residents according to the 2010 census.
The Beagle Channel's waters support populations of South American sea lions, southern fur seals, and multiple species of penguins. The channel's islands include breeding colonies of Magellanic penguins, with the largest concentrations on Martillo Island approximately 30 kilometers east of Ushuaia. King penguins, which typically breed on sub-Antarctic islands, established a small breeding colony on Martillo Island that researchers first documented in the 1990s, representing one of the northernmost breeding locations for this species. The Beagle Channel reaches depths of 400 meters in certain sections and maintains year-round navigation despite winter temperatures that regularly fall below freezing.
The Strait of Magellan, though primarily associated with Chilean territorial waters, intersects Argentine territory at its eastern entrance where it meets the Atlantic Ocean. The strait served as the primary shipping route between the Atlantic and Pacific oceans before the Panama Canal opened in 1914. Argentine control of eastern approaches to the strait contributed to historical territorial disputes with Chile, resolved through the 1984 Treaty of Peace and Friendship that confirmed Chilean sovereignty over islands in the Beagle Channel region.
Argentina's Atlantic coast includes several major river mouths beyond the Río de la Plata. The Colorado River, flowing approximately 1,000 kilometers from the Andes to the Atlantic, forms the northern boundary of Patagonia. The river's mouth sits near the town of San Antonio Oeste in Río Negro Province. The Negro River, approximately 635 kilometers long, flows eastward from its confluence with the Limay and Neuquén rivers in northern Patagonia, entering the Atlantic Ocean near the city of Viedma. The Chubut River in central Patagonia flows 810 kilometers from the Andes to the Atlantic, passing through the Welsh settlement region of the Chubut Valley where Welsh immigrants established agricultural communities beginning in 1865.
The Argentine coastal current flows northward along the continental shelf, bringing cold, nutrient-rich sub-Antarctic waters that support high biological productivity. Water temperatures along the Patagonian coast remain cold year-round, ranging from 6 to 15 degrees Celsius. The confluence of the cold northward-flowing current with warmer Brazil Current waters creates productive mixing zones between 33 and 38 degrees south latitude, supporting concentrations of anchovy, hake, and other commercial fish species.
The submarine plateau of the Burdwood Bank sits approximately 150 kilometers south of Tierra del Fuego, rising from the ocean floor to within 50 to 200 meters of the surface. The bank covers approximately 40,000 square kilometers and hosts unique benthic communities including cold-water corals. Argentina established the Namuncurá Marine Protected Area over the Burdwood Bank in 2013, covering 28,000 square kilometers and representing Argentina's first offshore marine protected area.
Commercial fishing in Argentine waters operates under quotas managed by the National Institute of Fisheries Research and Development. The fishing fleet operates primarily from Mar del Plata, Puerto Deseado, and Ushuaia. Argentine hake represents the highest-volume commercial species, with annual catches varying between 200,000 and 500,000 tons depending on quota allocations. Argentine red shrimp fisheries operate in waters deeper than 100 meters along the continental shelf break, targeting Pleoticus muelleri with annual catches of approximately 150,000 to 200,000 tons. Squid fisheries, primarily targeting Argentine shortfin squid (Illex argentinus), operate seasonally with highly variable catches ranging from 100,000 to 600,000 tons annually depending on environmental conditions and market factors.
The Paraná River system supports commercial fisheries distinct from ocean fisheries, targeting freshwater species including sábalo (Prochilodus lineatus), surubí (Pseudoplatystoma), and boga (Leporinus obtusidens). The sábalo fishery expanded significantly in the 2000s with development of export markets for fish meal and fish oil, with annual catches reaching 30,000 tons by 2010. Concerns about overfishing led to implementation of seasonal closures during spawning periods and restrictions on industrial-scale processing.
Navigable river systems extending beyond the Paraná-Río de la Plata include the Uruguay River, which forms Argentina's eastern border with Uruguay and southern Brazil. The river flows approximately 1,610 kilometers from its headwaters in Brazil to the Río de la Plata. Two major dams on the Uruguay River generate hydroelectric power: Salto Grande Dam, completed in 1979 on the Argentina-Uruguay border with installed capacity of 1,890 megawatts, and Yacyretá Dam on the Paraná. Regular barge traffic on the Uruguay River extends to the city of Concordia in Entre Ríos Province.
The Iguazú River, a tributary of the Paraná, flows along the border between Argentina and Brazil for approximately 380 kilometers before cascading over the Iguazú Falls. The falls system consists of approximately 275 individual waterfalls stretching 2.7 kilometers across the river, divided between Argentine and Brazilian territory. The highest individual cascade, known as Devil's Throat (Garganta del Diablo), measures 82 meters in height and 150 meters wide. Water flow over the falls varies seasonally from 500 cubic meters per second during dry periods to over 6,000 cubic meters per second during floods, with average flow approximately 1,750 cubic meters per second. The Argentine side of Iguazú Falls became a national park in 1934, and UNESCO designated both the Argentine and Brazilian park areas as World Heritage Sites in 1984 and 1986 respectively.
River port infrastructure on the Paraná and Río de la Plata handles bulk agricultural exports. The port of Rosario, located on the Paraná River approximately 470 kilometers upstream from Buenos Aires, operates as Argentina's primary grain export terminal. The Rosario port complex includes multiple private terminals that collectively handle over 40 million tons of grain and grain products annually, representing approximately 80 percent of Argentina's agricultural exports. Channel depth in the Paraná River between Rosario and the Atlantic requires continuous dredging to maintain depths of 34 feet (10.4 meters) allowing access for Panamax-class vessels. Dredging contracts have historically generated disputes over funding and environmental impacts.
The Paraguay River forms part of Argentina's northern border in the provinces of Formosa and Salta before flowing into Paraguay. The river supports commercial navigation connecting landlocked Paraguay and Bolivia to the Paraná-Río de la Plata system. Argentine ports on the Paraguay River include Formosa city and Clorinda, handling regional trade in timber, agricultural products, and manufactured goods. The Paraguay-Paraná Waterway, also known as Hidrovía, extends 3,442 kilometers from Puerto Cáceres in Brazil through Paraguay, Argentina, and Uruguay to the Río de la Plata, with ongoing infrastructure projects aimed at improving navigation conditions.
Coastal erosion affects portions of the Buenos Aires Province coastline, particularly in areas where construction has altered natural dune systems. The coastal city of Mar del Plata experiences erosion of beach sand requiring periodic replenishment programs. A major beach nourishment project in 2017 placed approximately 3 million cubic meters of sand along 10 kilometers of Mar del Plata coastline at a cost exceeding 50 million pesos.
The Argentine Navy maintains bases at Buenos Aires, Mar del Plata, Puerto Belgrano (near Bahía Blanca), and Ushuaia. Puerto Belgrano Naval Base, established in 1898, operates as the navy's primary operational base and includes ship maintenance facilities, weapons depots, and training facilities. The base suffered an explosion at its weapons depot in 1983 that killed 7 personnel and destroyed significant ammunition stockpiles.
Bahía Blanca, a port city in southern Buenos Aires Province with a population of approximately 301,000, operates Argentina's deepest natural harbor with depths reaching 45 feet (13.7 meters) without dredging. The port handles grain exports, petroleum products, and petrochemical exports from nearby industrial facilities. The port's Ingeniero White terminal complex includes facilities for loading grains, vegetable oils, and containers. Annual cargo volumes at Bahía Blanca exceed 20 million tons.
The Limay River and Neuquén River converge near the city of Neuquén in northern Patagonia, forming the Negro River. A series of five dams on the Limay River generates hydroelectric power, including Alicurá Dam (1,000 megawatts), Piedra del Águila Dam (1,400 megawatts), and Pichi Picún Leufú Dam (260 megawatts). These dams regulate water flow in the Negro River system and provide irrigation water for the Alto Valle fruit-growing region around the cities of Neuquén, Cipolletti, and General Roca.
Argentine maritime territory extends to the 200-nautical-mile exclusive economic zone established under the United Nations Convention on the Law of the Sea. Argentina claims sovereignty over the Falkland Islands (Islas Malvinas), South Georgia and the South Sandwich Islands, all currently administered by the United Kingdom. The 1982 Falklands War resulted from Argentina's military occupation of the islands in April 1982, followed by British military operations that reclaimed the islands by June 1982. The conflict resulted in 649 Argentine military deaths, 255 British deaths, and 3 Falkland Islander deaths. Argentina continues to assert sovereignty claims through diplomatic channels while the United Kingdom maintains effective control and a military garrison on the islands.
The continental shelf waters off Argentina host significant undeveloped hydrocarbon reserves. Offshore exploration activities expanded in the 2010s with deepwater drilling in the Argentina Basin and waters off Tierra del Fuego. The Austral Basin offshore area contains proven gas reserves, with production platforms operating in waters near Tierra del Fuego supplying gas to the city of Río Gallegos and export facilities. Offshore exploration in the Malvinas Basin west of the Falkland Islands remains contentious due to the sovereignty dispute.
Coastal Patagonian cities developed around sheep ranching and port functions in the late 19th and early 20th centuries. Puerto Deseado in Santa Cruz Province, with a population of approximately 15,000, operates fishing port facilities and serves as a departure point for visits to offshore wildlife colonies. Río Gallegos, the capital of Santa Cruz Province with a population of approximately 98,000, sits on the estuary of the Gallegos River approximately 30 kilometers from the Atlantic coast. The city functions as an administrative center and transportation hub for southern Patagonia.
The Valdez oil terminal at Punta Loyola, approximately 10 kilometers south of Río Gallegos, handles crude oil exports from Santa Cruz Province oil fields. The terminal, operational since 1984, loads tankers through an offshore buoy system in waters too shallow for tanker access to shore. A 78-kilometer pipeline connects inland oil fields to the terminal.
Lake systems in Patagonia, though not coastal in the oceanic sense, include large bodies of water along the Andes cordillera that drain toward both the Pacific and Atlantic oceans. Lake Nahuel Huapi in Río Negro and Neuquén provinces covers 557 square kilometers at an elevation of 767 meters. The lake reaches depths of 464 meters and drains through the Limay River to the Atlantic. The city of San Carlos de Bariloche, with a population of approximately 112,000, sits on the southern shore of Lake Nahuel Huapi and operates as a tourist destination for lake recreation and winter skiing.