At 165,250,000 square kilometers (63,800,000 square miles) in area (as defined with a southern Antarctic border), the Pacific Ocean is the largest division of theWorld Ocean and thehydrosphere and covers approximately 46% of Earth's water surface and about 32% of the planet's total surface area, larger than its entire land area (148,000,000 km2 (57,000,000 sq mi)).[1] The centers of both thewater hemisphere and theWestern Hemisphere, as well as theoceanic pole of inaccessibility, are in the Pacific Ocean. Ocean circulation (caused by theCoriolis effect) subdivides it[2] into two largely independent volumes of water that meet at theequator, theNorth Pacific Ocean and theSouth Pacific Ocean (or more loosely theSouth Seas). The Pacific Ocean can also be informally divided by theInternational Date Line into theEast Pacific and theWest Pacific, which allows it to be further divided into four quadrants, namely theNortheast Pacific off the coasts ofNorth America, theSoutheast Pacific offSouth America, theNorthwest Pacific offFar Eastern/Pacific Asia, and theSouthwest Pacific aroundOceania.
The Pacific Ocean's mean depth is 4,000 meters (13,000 feet).[3] TheChallenger Deep in theMariana Trench, located in the northwestern Pacific, is the deepest known point in the world, reaching a depth of 10,928 meters (35,853 feet).[4] The Pacific also contains the deepest point in theSouthern Hemisphere, theHorizon Deep in theTonga Trench, at 10,823 meters (35,509 feet).[5] The third deepest point on Earth, theSirena Deep, was also located in the Mariana Trench. It is the warmest ocean, as its temperatures can reach as high as 31°C (88°F) due to it surrounding major and minor Pacific islands, which have a tropical, hot climate.[6]
In the early 16th century,Spanish explorerVasco Núñez de Balboa crossed theIsthmus of Panama in 1513 and sighted the great "Southern Sea", which he namedMar del Sur (in Spanish). Afterwards, the ocean's current name was coined by Portuguese explorerFerdinand Magellan during the Spanishcircumnavigation of the world in 1520, as he encountered favorable winds upon reaching the ocean. He called itMar Pacífico, which in Portuguese means 'peaceful sea'.[7][8]
Across the continents ofAsia,Australia and theAmericas, more than 25,000 islands, large and small, rise above the surface of the Pacific Ocean. Multiple islands were the shells of former activevolcanoes that have lain dormant for thousands of years. Close to the equator, without vast areas of blue ocean, are a dot ofatolls that have over intervals of time been formed byseamounts as a result of tiny coral islands strung in a ring within surroundings of a centrallagoon.
Important human migrations occurred in the Pacific in prehistoric times. Modern humans first reached the western Pacific in thePaleolithic, at around 60,000 to 70,000 years ago. Originating from a southern coastal human migration out of Africa, they reachedEast Asia,Mainland Southeast Asia, the Philippines,New Guinea, and then Australia by making the sea crossing of at least 80 kilometres (50 mi) betweenSundaland andSahul. It is not known with any certainty what level of maritime technology was used by these groups – the presumption is that they used large bamboo rafts which may have been equipped with some sort of sail. The reduction in favourable winds for a crossing to Sahul after 80,000 B.P. fits with the dating of the settlement of Australia, with no later migrations in the prehistoric period. The seafaring abilities of pre-Austronesian residents of Island South-east Asia are confirmed by the settlement ofBuka by 32,000 B.P. andManus by 25,000 B.P. Journeys of 180 kilometres (110 mi) and 230 kilometres (140 mi) are involved, respectively.[9]
At around 1300 to 1200 BCE, a branch of the Austronesian migrations known as theLapita culture reached theBismarck Archipelago, theSolomon Islands,Vanuatu,Fiji, andNew Caledonia. From there, they settledTonga andSamoa by 900 to 800 BCE. Some also back-migrated northwards in 200 BCE to settle the islands of easternMicronesia (including theCarolines, theMarshall Islands, andKiribati), mixing with earlier Austronesian migrations in the region. This remained the furthest extent of the Austronesian expansion intoPolynesia until around 700 CE when there was another surge of island exploration. They reached theCook Islands,Tahiti, and theMarquesas by 700 CE;Hawaiʻi by 900 CE;Rapa Nui by 1000 CE; and finally New Zealand by 1200 CE.[14][17][18] Austronesians may have also reached as far as theAmericas, although evidence for this remains inconclusive.[19][20]
Universalis Cosmographia, also known as theWaldseemüller map, dated 1507, was the first map to show theAmericas separating two distinct oceans. South America was generally considered theNew World and shows the name "America" for the first time, afterAmerigo Vespucci
The eastern side of the ocean was encountered by Spanish explorerVasco Núñez de Balboa in 1513 after his expedition crossed theIsthmus of Panama and reached a new ocean.[24] He named itMar del Sur ("Sea of the South" or"South Sea") because the ocean was to the south of the coast of the isthmus where he first observed the Pacific.
In 1520, navigatorFerdinand Magellan and his crew were the first to cross the Pacific in recorded history. They were part of aSpanish expedition to theSpice Islands that would eventually result in the first worldcircumnavigation. Magellan called the oceanPacífico (or "Pacific" meaning, "peaceful") because, after sailing through the stormy seas offCape Horn, the expedition found calm waters. The ocean was often called theSea of Magellan in his honor until the eighteenth century.[25] Magellan stopped at one uninhabited Pacific island before stopping atGuam in March 1521.[26] Although Magellan himself died in thePhilippines in 1521, Spanish navigatorJuan Sebastián Elcano led the remains of the expedition back to Spain across theIndian Ocean and round theCape of Good Hope, completing the first world circumnavigation in 1522.[27] Sailing around and east of the Moluccas, between 1525 and 1527, Portuguese expeditions encountered theCaroline Islands,[28] theAru Islands,[29] andPapua New Guinea.[30] In 1542–43 the Portuguese also reached Japan.[31]
Later, in the quest forTerra Australis ("the [great] Southern Land"), Spanish explorations in the 17th century, such as the expedition led by the Portuguese navigatorPedro Fernandes de Queirós, arrived at thePitcairn andVanuatu archipelagos, and sailed theTorres Strait between Australia and New Guinea, named after navigatorLuís Vaz de Torres. Dutch explorers, sailing around southern Africa, also engaged in exploration and trade;Willem Janszoon, made the first completely documented European landing in Australia (1606), inCape York Peninsula,[34] andAbel Janszoon Tasman circumnavigated and landed on parts of the Australian continental coast and arrived atTasmania and New Zealand in 1642.[35]
In the 16th and 17th centuries, Spain considered the Pacific Ocean amare clausum – a sea closed to other naval powers. As the only known entrance from the Atlantic, theStrait of Magellan was at times patrolled by fleets sent to prevent the entrance of non-Spanish ships. On the western side of the Pacific Ocean the Dutch threatened theSpanish Philippines.[36]
Growingimperialism during the 19th century resulted in the occupation of much of Oceania by European powers, and later Japan and the United States. Significant contributions to oceanographic knowledge were made by the voyages ofHMSBeagle in the 1830s, withCharles Darwin aboard;[39]HMSChallenger during the 1870s;[40] theUSSTuscarora (1873–76);[41] and the GermanGazelle (1874–76).[42]
In Oceania, France obtained a leading position as imperial power after makingTahiti andNew Caledonia protectorates in 1842 and 1853, respectively.[43] After navy visits toEaster Island in 1875 and 1887, Chilean navy officerPolicarpo Toro negotiated the incorporation of the island into Chile with nativeRapanui in 1888. By occupying Easter Island, Chile joined the imperial nations.[44]: 53 By 1900 nearly all Pacific islands were in control of Britain, France, United States, Germany, Japan, and Chile.[43]
Although the United States gained control ofGuam and the Philippines from Spain in 1898,[45] Japan controlled most of the western Pacific by 1914 and occupied many other islands during thePacific War; however, by the end of that war, Japan was defeated and theU.S. Pacific Fleet was the virtual master of the ocean. The Japanese-ruledNorthern Mariana Islands came under the control of the United States.[46] Since the end of World War II, many former colonies in the Pacific have become independentstates.
The Pacific separates Asia and Australia from the Americas. It may be further subdivided by the equator into northern (North Pacific) and southern (South Pacific) portions. It extends from theAntarctic region in the South to theArctic in the north.[1] The Pacific Ocean encompasses approximately one-third of the Earth's surface, having an area of 165,200,000 km2 (63,800,000 sq mi) – larger than Earth's entire landmass combined, 150,000,000 km2 (58,000,000 sq mi).[47]
Extending approximately 15,500 km (9,600 mi) from theBering Sea in theArctic to the northern extent of the circumpolarSouthern Ocean at60°S (older definitions extend it toAntarctica'sRoss Sea), the Pacific reaches its greatest east–west width at about5°N latitude, where it stretches approximately 19,800 km (12,300 mi) from Indonesia to the coast ofColombia – halfway around the world, and more than five times the diameter of the Moon.[48] Its geographic center is in easternKiribati south ofKiritimati, just west fromStarbuck Island at4°58′S158°45′W / 4.97°S 158.75°W /-4.97; -158.75.[49] The lowest known point on Earth – theMariana Trench – lies 10,911 m (35,797 ft; 5,966fathoms) below sea level. Its average depth is 4,280 m (14,040 ft; 2,340 fathoms), putting the total water volume at roughly 710,000,000 km3 (170,000,000 cu mi).[1]
Due to the effects ofplate tectonics, the Pacific Ocean is currently shrinking by roughly 2.5 cm (1 in) per year on three sides, roughly averaging 0.52 km2 (0.20 sq mi) a year. By contrast, the Atlantic Ocean is increasing in size.[50][51]
For most of Magellan's voyage from theStrait of Magellan to thePhilippines, the explorer indeed found the ocean peaceful; however, the Pacific is not always peaceful. Manytropical storms batter the islands of the Pacific.[54] The lands around thePacific Rim are full ofvolcanoes and often affected byearthquakes.Tsunamis, caused by underwater earthquakes, have devastated many islands and in some cases destroyed entire towns.[55]
TheMartin Waldseemüller map of 1507 was the first to show the Americas separating two distinct oceans.[56] Later, theDiogo Ribeiro map of 1529 was the first to show the Pacific at about its proper size.[57]
An exclusive economic zone (EEZ) map of the Pacific
(Inhabited dependent territories are denoted by the asterisk (*), with names of the corresponding sovereign states in round brackets. Associated states in the Realm of New Zealand are denoted by the hash sign (#).)
Islands in the Pacific Ocean are of four basic types: continental islands, high islands, coral reefs and uplifted coral platforms. Continental islands lie outside the andesite line and include New Guinea, the islands of New Zealand, and the Philippines. Some of these islands are structurally associated with nearby continents. High islands are of volcanic origin, and many contain active volcanoes. Among these areBougainville, Hawaii, and the Solomon Islands.[65]
Thecoral reefs of the South Pacific are low-lying structures that have built up on basaltic lava flows under the ocean's surface. One of the most dramatic is theGreat Barrier Reef off northeastern Australia with chains of reef patches. A second island type formed of coral is the uplifted coral platform, which is usually slightly larger than the low coral islands. Examples includeBanaba (formerly Ocean Island) andMakatea in the Tuamotu group ofFrench Polynesia.[66][67]
The volume of the Pacific Ocean, representing about 50.1 percent of the world's oceanic water, has been estimated at some 714 million cubic kilometers (171 million cubic miles).[68] Surface water temperatures in the Pacific can vary from −1.4 °C (29.5 °F), the freezing point of seawater, in the poleward areas to about 30 °C (86 °F) near the equator.[69]Salinity also varies latitudinally, reaching a maximum of 37 parts per thousand in the southeastern area. The water near the equator, which can have a salinity as low as 34 parts per thousand, is less salty than that found in the mid-latitudes because of abundant equatorial precipitation throughout the year. The lowest counts of less than 32 parts per thousand are found in the far north as less evaporation of seawater takes place in these frigid areas.[70] The motion of Pacific waters is generally clockwise in theNorthern Hemisphere (theNorth Pacific gyre) and counter-clockwise in theSouthern Hemisphere. TheNorth Equatorial Current, driven westward alonglatitude 15°N by thetrade winds, turns north near the Philippines to become the warm Japan orKuroshio Current.[71]
Turning eastward at about45°N, the Kuroshio forks and some water moves northward as theAleutian Current, while the rest turns southward to rejoin the North Equatorial Current.[72] The Aleutian Current branches as it approaches North America and forms the base of a counter-clockwise circulation in theBering Sea. Its southern arm becomes the chilled slow, south-flowingCalifornia Current.[73] TheSouth Equatorial Current, flowing west along the equator, swings southward east ofNew Guinea, turns east at about50°S, and joins the main westerly circulation of the South Pacific, which includes the Earth-circlingAntarctic Circumpolar Current. As it approaches the Chilean coast, the South Equatorial Current divides; one branch flows aroundCape Horn and the other turns north to form the Peru orHumboldt Current.[74]
The climate patterns of the Northern and Southern Hemispheres generally mirror each other. Thetrade winds in the southern and eastern Pacific are remarkably steady while conditions in the North Pacific are far more varied with, for example, cold winter temperatures on the east coast of Russia contrasting with the milder weather offBritish Columbia during the winter months due to the preferred flow ofocean currents.[75]
In the tropical and subtropical Pacific, theEl Niño Southern Oscillation (ENSO) affects weather conditions. To determine the phase of ENSO, the most recent three-monthsea surface temperature average for the area approximately 3,000 km (1,900 mi) to the southeast ofHawaii is computed, and if the region is more than 0.5 °C (0.9 °F) above or below normal for that period, then anEl Niño orLa Niña is considered in progress.[76]
In September 2025, NOAA reported that global ocean surface temperatures remained at near-record levels, with June–August 2025 ranking as the third warmest in their 176-year record.[77]
In the tropical western Pacific, themonsoon and the relatedwet season during the summer months contrast with dry winds in the winter which blow over the ocean from the Asian landmass.[78] Worldwide,tropical cyclone activity peaks in late summer, when the difference between temperatures aloft and sea surface temperatures is the greatest; however, each particular basin has its own seasonal patterns. On a worldwide scale, May is the least active month, while September is the most active month. November is the only month in which all thetropical cyclone basins are active.[79] The Pacific hosts the two most activetropical cyclone basins, which are the northwestern Pacific and the eastern Pacific.Pacific hurricanes form south of Mexico, sometimes striking the western Mexican coast and occasionally the Southwestern United States between June and October, whiletyphoons forming in the northwestern Pacific moving into southeast and east Asia from May to December. Tropical cyclones also form in theSouth Pacific basin, where they occasionally impact island nations.[80]
In the arctic, icing from October to May can present a hazard for shipping while persistent fog occurs from June to December.[81] A climatological low in the Gulf of Alaska keeps the southern coast wet and mild during the winter months. TheWesterlies and associatedjet stream within the Mid-Latitudes can be particularly strong, especially in the Southern Hemisphere, due to the temperature difference between the tropics and Antarctica,[82] which records the coldest temperature readings on the planet. In the Southern hemisphere, because of the stormy and cloudy conditions associated withextratropical cyclones riding the jet stream, it is usual to refer to the Westerlies as the Roaring Forties, Furious Fifties and Shrieking Sixties according to the varying degrees of latitude.[83]
The ocean was first mapped byAbraham Ortelius; he called it Maris Pacifici followingFerdinand Magellan's description of it as "a pacific sea" during his circumnavigation from 1519 to 1522. To Magellan, it seemed much more calm (pacific) than the Atlantic.[84]
The dissimilarity continues northeastward along the western edge of theAndesCordillera along South America to Mexico, returning then to the islands off California. Indonesia, the Philippines, Japan, New Guinea, and New Zealand lie outside the andesite line.
Within the closed loop of the andesite line are most of the deep troughs, submerged volcanic mountains, and oceanic volcanic islands that characterize the Pacific basin. Here basaltic lavas gently flow out of rifts to build huge dome-shaped volcanic mountains whose eroded summits form island arcs, chains, and clusters. Outside the andesite line, volcanism is of the explosive type, and the PacificRing of Fire is the world's foremost belt of explosivevolcanism.[61] The Ring of Fire is named after the several hundred active volcanoes that sit above the various subduction zones.
The Pacific Ocean is the only ocean which is mostly bounded bysubduction zones. Only the central part of the North American coast and the Antarctic and Australian coasts have no nearby subduction zones.
The Pacific Ocean was born 750million years ago at the breakup ofRodinia, although it is generally called thePanthalassa until the breakup ofPangea, about 200million years ago.[88] The oldest Pacific Ocean floor is only around 180Ma old, with older crust subducted by now.[89]
The exploitation of the Pacific's mineral wealth is hampered by the ocean's great depths. In shallow waters of the continental shelves off the coasts of Australia and New Zealand,petroleum andnatural gas are extracted, andpearls are harvested along the coasts of Australia, Japan,Papua New Guinea, Nicaragua, Panama, and the Philippines, although in sharply declining volume in some cases.[90]
Fish are an important economic asset in the Pacific. The shallower shoreline waters of the continents and the more temperate islands yieldherring,salmon,sardines,snapper,swordfish, andtuna, as well asshellfish.[91]Overfishing has become a serious problem in some areas. Overfishing leads to depleted fish populations and closed fisheries, causing both economic and ecologic consequences.[92] For example, catches in the rich fishing grounds of theOkhotsk Sea off the Russian coast have been reduced by at least half since the 1990s as a result of overfishing.[93]
Pacific Ocean currents have created three islands of debris.[94]Marine debris on aHawaiian coast in 2008
The Northwestern Pacific Ocean is most susceptible to micro plastic pollution due to its proximity to highly populated countries like Japan and China.[95] The quantity of small plastic fragments floating in the north-east Pacific Ocean increased a hundredfold between 1972 and 2012.[96][verification needed] The ever-growingGreat Pacific Garbage Patch between California and Japan is three times the size of France.[97] An estimated 80,000 metric tons of plastic inhabit the patch, totaling 1.8trillion pieces.[98]
Marine pollution is a generic term for the harmful entry into the ocean of chemicals or particles. The main culprits are those using the rivers for disposing of their waste.[99] The rivers then empty into the ocean, often also bringing chemicals used asfertilizers in agriculture. The excess of oxygen-depleting chemicals in the water leads tohypoxia and the creation of adead zone.[100]
Marine debris, also known as marine litter, is human-created waste that has ended up floating in a lake, sea, ocean, or waterway. Oceanic debris tends to accumulate at the center of gyres and coastlines, frequently washing aground where it is known as beach litter.[99]
An emerging threat for the Pacific Ocean is the development ofdeep-sea mining.Deep-sea mining is aimed at extractingmanganese nodules that contain minerals such as magnesium, nickel, copper, zinc and cobalt. The largest deposits of these are found in the Pacific Ocean between Mexico and Hawaii in theClarion Clipperton fracture zone.
Deep-sea mining for manganese nodules appears to have drastic consequences for the ocean. It disrupts deep-sea ecosystems and may cause irreversible damage to fragile marine habitats.[108] Sediment stirring and chemical pollution threaten various marine animals. In addition, the mining process can lead to greenhouse gas emissions and promote further climate change. Preventing deep-sea mining is therefore important to ensure the long-term health of the ocean.[109]
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^Winter, Olaf; Clark, Geoffrey; Anderson, Atholl; Lindahl, Anders (September 2012). "Austronesian sailing to the northern Marianas, a comment on Hung et al. (2011)".Antiquity.86 (333):898–910.doi:10.1017/S0003598X00047992.ISSN0003-598X.S2CID161735451.
^Pawley A (2002). "The Austronesian dispersal: languages, technologies and people". In Bellwood PS, Renfrew C (eds.).Examining the farming/language dispersal hypothesis. McDonald Institute for Archaeological Research, University of Cambridge. pp. 251–273.ISBN978-1902937205.
^Van Tilburg, Jo Anne. 1994.Easter Island: Archaeology, Ecology and Culture. Washington D.C.: Smithsonian Institution Press
^Langdon, Robert. The Bamboo Raft as a Key to the Introduction of the Sweet Potato in Prehistoric Polynesia,The Journal of Pacific History, Vol. 36, No. 1, 2001
^Hannard, Willard A. (1991).Indonesian Banda: Colonialism and its Aftermath in the Nutmeg Islands.Bandanaira: Yayasan Warisan dan Budaya Banda Naira. p. 7.
^Kratoska, Paul H. (2001).South East Asia, Colonial History: Imperialism before 1800, Volume 1 de South East Asia, Colonial History. Taylor & Francis. pp. 52–56.[1]
^The Covenant to Establish a Commonwealth of the Northern Mariana Islands in Political Union With the United States of America,Pub. L.94–241, 90 Stat.263, enactedMarch 24, 1976
^"Great Pacific Garbage Patch".Marine Debris Division – Office of Response and Restoration. NOAA. 11 July 2013.Archived from the original on 17 April 2014.
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NOAA TAOEl Niño data Realtime Pacific Ocean El Niño buoy data
NOAA Ocean Surface Current Analyses – Realtime (OSCAR) Near-realtime Pacific Ocean Surface Currents derived from satellite altimeter and scatterometer data
![Maris Pacifici by Ortelius (1589). One of the first printed maps to show the Pacific Ocean[38]](/mt/?noimg=&dark=on&url=http%3a%2f%2fen.wikipedia.org%2fwiki%2fFile%3aOrtelius_-_Maris_Pacifici_1589.jpg)
_over_the_Marianas_Trench%2c_23_January_1960_(NH_96797).jpg)
