The Pacific Ocean is the largest and deepest of
Earth's five
oceanic divisions. It extends from the
Arctic Ocean in the north to the
Southern Ocean, or, depending on the definition, to
Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. ...
in the south, and is bounded by the continents of
Asia and
Australia
Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...
in the west and the
Americas
The Americas, sometimes collectively called America, are a landmass comprising the totality of North America and South America.''Webster's New World College Dictionary'', 2010 by Wiley Publishing, Inc., Cleveland, Ohio. When viewed as a sing ...
in the east.
At in area (as defined with a southern Antarctic border), the Pacific Ocean is the largest division of the
World Ocean and the
hydrosphere 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 ().
[Pacific Ocean]
. '' Britannica Concise.'' 2008: Encyclopædia Britannica, Inc. The centers of both the
water hemisphere and the
Western Hemisphere, as well as the
oceanic pole of inaccessibility, are in the Pacific Ocean. Ocean circulation (caused by the
Coriolis effect) subdivides it into two largely independent volumes of water that meet at the
equator
The equator is the circle of latitude that divides Earth into the Northern Hemisphere, Northern and Southern Hemisphere, Southern Hemispheres of Earth, hemispheres. It is an imaginary line located at 0 degrees latitude, about in circumferen ...
, the North Pacific Ocean and the South Pacific Ocean (or more loosely the
South Seas). The Pacific Ocean can also be informally divided by the
International Date Line into the East Pacific and the West Pacific, which allows it to be further divided into four quadrants, namely the Northeast Pacific off the coasts of
North America
North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...
, the Southeast Pacific off
South America, the Northwest Pacific off
Far Eastern/
Pacific Asia, and the Southwest Pacific around
Oceania.
The Pacific Ocean's mean depth is . The
Challenger Deep in the
Mariana Trench, located in the northwestern Pacific, is the deepest known point in the world, reaching a depth of . The Pacific also contains the deepest point in the
Southern Hemisphere, the
Horizon Deep in the
Tonga Trench, at . The third deepest point on Earth, the
Sirena Deep, was also located in the Mariana Trench.
The western Pacific has many major
marginal seas, including the
Philippine Sea,
South China Sea,
East China Sea,
Sea of Japan,
Sea of Okhotsk,
Bering Sea
The Bering Sea ( , ; rus, Бе́рингово мо́ре, r=Béringovo móre, p=ˈbʲerʲɪnɡəvə ˈmorʲe) is a marginal sea of the Northern Pacific Ocean. It forms, along with the Bering Strait, the divide between the two largest landmasse ...
,
Gulf of Alaska,
Gulf of California,
Mar de Grau,
Tasman Sea, and the
Coral Sea.
It is the warmest of all the oceans, as its temperatures can reach 31°C (88°F) due to it surrounding major and minor Pacific islands, which have a tropical, hot climate.
Etymology
In the early 16th century, Spanish explorer
Vasco Núñez de Balboa crossed the
Isthmus of Panama in 1513 and sighted the great "Southern Sea", which he named (in Spanish). Afterwards, the ocean's current name was coined by Portuguese explorer
Ferdinand Magellan during the Spanish
circumnavigation of the world in 1521, as he encountered favorable winds upon reaching the ocean. He called it , which in Portuguese means 'peaceful sea'.
History
Prehistory
Across the continents of Asia,
Australia
Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...
and the
Americas
The Americas, sometimes collectively called America, are a landmass comprising the totality of North America and South America.''Webster's New World College Dictionary'', 2010 by Wiley Publishing, Inc., Cleveland, Ohio. When viewed as a sing ...
, more than 25,000 islands, large and small, rise above the surface of the Pacific Ocean. Multiple islands were the shells of former active
volcano
A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.
On Earth, volcanoes are most oft ...
es that have lain dormant for thousands of years. Close to the equator, without vast areas of blue ocean, are a dot of
atolls that have over intervals of time been formed by
seamounts as a result of tiny coral islands strung in a ring within surroundings of a central
lagoon.
Early migrations
Important human migrations occurred in the Pacific in prehistoric times. Modern humans first reached the western Pacific in the
Paleolithic, at around 60,000 to 70,000 years ago. Originating from a southern coastal human migration out of Africa, they reached
East Asia,
Mainland Southeast Asia, the Philippines,
New Guinea
New Guinea (; Hiri Motu: ''Niu Gini''; , fossilized , also known as Papua or historically ) is the List of islands by area, world's second-largest island, with an area of . Located in Melanesia in the southwestern Pacific Ocean, the island is ...
, and then Australia by making the sea crossing of at least between
Sundaland and
Sahul. It is not known with any certainty what level of maritime technology was used by these groupsthe 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 58,000 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 of
Buka by 32,000 B.P. and
Manus by 25,000 B.P. Journeys of and are involved, respectively.
The descendants of these migrations today are the
Negritos,
Melanesians, and
Indigenous Australians
Indigenous Australians are people with familial heritage from, or recognised membership of, the various ethnic groups living within the territory of contemporary Australia prior to History of Australia (1788–1850), British colonisation. The ...
. Their populations in
maritime Southeast Asia
Maritime Southeast Asia comprises the Southeast Asian countries of Brunei, Indonesia, Malaysia, the Philippines, Singapore, and East Timor.
The terms Island Southeast Asia and Insular Southeast Asia are sometimes given the same meaning as ...
, coastal
New Guinea
New Guinea (; Hiri Motu: ''Niu Gini''; , fossilized , also known as Papua or historically ) is the List of islands by area, world's second-largest island, with an area of . Located in Melanesia in the southwestern Pacific Ocean, the island is ...
, and
Island Melanesia later intermarried with the incoming
Austronesian settlers from
Taiwan
Taiwan, officially the Republic of China (ROC), is a country in East Asia. The main geography of Taiwan, island of Taiwan, also known as ''Formosa'', lies between the East China Sea, East and South China Seas in the northwestern Pacific Ocea ...
and the northern
Philippines
The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...
, but also earlier groups associated with
Austroasiatic-speakers, resulting in the modern peoples of Island Southeast Asia and Oceania.

A later seaborne migration is the
Neolithic
The Neolithic or New Stone Age (from Ancient Greek, Greek 'new' and 'stone') is an archaeological period, the final division of the Stone Age in Mesopotamia, Asia, Europe and Africa (c. 10,000 BCE to c. 2,000 BCE). It saw the Neolithic Revo ...
Austronesian expansion of the
Austronesian peoples. Austronesians originated from the island of
Taiwan
Taiwan, officially the Republic of China (ROC), is a country in East Asia. The main geography of Taiwan, island of Taiwan, also known as ''Formosa'', lies between the East China Sea, East and South China Seas in the northwestern Pacific Ocea ...
–1500 BCE. They are associated with distinctive maritime sailing technologies (notably
outrigger boats,
catamarans,
lashed-lug boats, and the
crab claw sail)it is likely that the progressive development of these technologies were related to the later steps of settlement into Near and Remote Oceania. Starting at around 2200 BCE, Austronesians sailed southwards to settle the
Philippines
The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...
. From, probably, the
Bismarck Archipelago they crossed the western Pacific to reach the
Marianas Islands by 1500 BCE, as well as
Palau and
Yap by 1000 BCE. They were the first humans to reach
Remote Oceania, and the first to cross vast distances of open water. They also continued spreading southwards and settling the rest of
Maritime Southeast Asia
Maritime Southeast Asia comprises the Southeast Asian countries of Brunei, Indonesia, Malaysia, the Philippines, Singapore, and East Timor.
The terms Island Southeast Asia and Insular Southeast Asia are sometimes given the same meaning as ...
, reaching
Indonesia
Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...
and
Malaysia by 1500 BCE, and further west to
Madagascar
Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...
and the
Comoros in the
Indian Ocean by around 500 CE.
More recently, it is suggested that Austronesians expanded already earlier, arriving in the Philippines already in 7000 BCE. Additional earlier migrations into Insular Southeast Asia, associated with Austroasiatic-speakers from Mainland Southeast Asia, are estimated to have taken place already in 15000 BCE.
At around 1300 to 1200 BCE, a branch of the Austronesian migrations known as the
Lapita culture reached the
Bismarck Archipelago, the
Solomon Islands,
Vanuatu,
Fiji
Fiji, officially the Republic of Fiji, is an island country in Melanesia, part of Oceania in the South Pacific Ocean. It lies about north-northeast of New Zealand. Fiji consists of an archipelago of more than 330 islands—of which about ...
, and
New Caledonia. From there, they settled
Tonga and
Samoa by 900 to 800 BCE. Some also back-migrated northwards in 200 BCE to settle the islands of eastern
Micronesia (including the
Carolines, the
Marshall Islands, and
Kiribati), mixing with earlier Austronesian migrations in the region. This remained the furthest extent of the Austronesian expansion into
Polynesia until around 700 CE when there was another surge of island exploration. They reached the
Cook Islands,
Tahiti, and the
Marquesas by 700 CE;
Hawaii
Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...
by 900 CE;
Rapa Nui by 1000 CE; and finally New Zealand by 1200 CE.
Austronesians may have also reached as far as the
Americas
The Americas, sometimes collectively called America, are a landmass comprising the totality of North America and South America.''Webster's New World College Dictionary'', 2010 by Wiley Publishing, Inc., Cleveland, Ohio. When viewed as a sing ...
, although evidence for this remains inconclusive.
European exploration

The first contact of European navigators with the western edge of the Pacific Ocean was made by the Portuguese expeditions of
António de Abreu and
Francisco Serrão, via the
Lesser Sunda Islands, to the
Maluku Islands, in 1512, and with
Jorge Álvares's expedition to southern China in 1513,
[Porter, Jonathan. (1996). ''Macau, the Imaginary City: Culture and Society, 1557 to the Present''. Westview Press. ] both ordered by
Afonso de Albuquerque from
Malacca.
The eastern side of the ocean was encountered by Spanish explorer
Vasco Núñez de Balboa in 1513 after his expedition crossed the
Isthmus of Panama and reached a new ocean.
He named it ''Mar 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, navigator
Ferdinand Magellan and his crew were the first to cross the Pacific in recorded history. They were part of a
Spanish expedition to the
Spice Islands that would eventually result in the first world
circumnavigation. Magellan called the ocean ''Pacífico'' (or "Pacific" meaning, "peaceful") because, after sailing through the stormy seas off
Cape Horn, the expedition found calm waters. The ocean was often called the Sea of Magellan in his honor until the eighteenth century. Magellan stopped at one uninhabited Pacific island before stopping at
Guam in March 1521. Although Magellan himself died in the
Philippines
The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...
in 1521, Spanish navigator
Juan Sebastián Elcano led the remains of the expedition back to Spain across the
Indian Ocean and round the
Cape of Good Hope, completing the first world circumnavigation in 1522.
["Life in the sea: Pacific Ocean"]
Oceanário de Lisboa. Retrieved 9 June 2013. Sailing around and east of the Moluccas, between 1525 and 1527, Portuguese expeditions encountered the
Caroline Islands, the
Aru Islands, and
Papua New Guinea.
In 1542–43 the Portuguese also reached Japan.
In 1564, five Spanish ships carrying 379 soldiers crossed the ocean from Mexico led by
Miguel López de Legazpi, and colonized the
Philippines
The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...
and
Mariana Islands.
For the remainder of the 16th century, Spain maintained military and mercantile control, with ships sailing from Mexico and
Peru
Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...
across the Pacific Ocean to the Philippines via
Guam, and establishing the
Spanish East Indies. The
Manila galleon
The Manila galleon (; ) refers to the Spain, Spanish trading Sailing ship, ships that linked the Philippines in the Spanish East Indies to Mexico (New Spain), across the Pacific Ocean. The ships made one or two round-trip voyages per year betwe ...
s operated for two and a half centuries, linking
Manila and
Acapulco, in one of the longest trade routes in history. Spanish expeditions also arrived at
Tuvalu, the
Marquesas, the
Cook Islands, the
Solomon Islands,
Vanuatu, the
Marshalls and the
Admiralty Islands in the South Pacific.
Later, in the quest for
Terra Australis ("the
reatSouthern Land"), Spanish explorations in the 17th century, such as the expedition led by the Portuguese navigator
Pedro Fernandes de Queirós, arrived at the
Pitcairn and
Vanuatu archipelagos, and sailed the
Torres Strait between Australia and New Guinea, named after navigator
Luís 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), in
Cape York Peninsula, and
Abel Janszoon Tasman circumnavigated and landed on parts of the Australian continental coast and arrived at
Tasmania
Tasmania (; palawa kani: ''Lutruwita'') is an island States and territories of Australia, state of Australia. It is located to the south of the Mainland Australia, Australian mainland, and is separated from it by the Bass Strait. The sta ...
and New Zealand in 1642.
In the 16th and 17th centuries, Spain considered the Pacific Ocean a ''
mare clausum''a sea closed to other naval powers. As the only known entrance from the Atlantic, the
Strait 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 the
Spanish Philippines.
The 18th century marked the beginning of major exploration by the Russians in
Alaska
Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...
and the
Aleutian Islands, such as the
First Kamchatka expedition and the
Great Northern Expedition, led by the Danish-born Russian navy officer
Vitus Bering. Spain also sent
expeditions to the Pacific Northwest, reaching
Vancouver Island in southern Canada, and Alaska. The French explored and colonized
Polynesia, and the British made three voyages with
James Cook to the South Pacific and Australia,
Hawaii
Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...
, and the North American
Pacific Northwest. In 1768,
Pierre-Antoine Véron, a young
astronomer accompanying
Louis Antoine de Bougainville on his voyage of exploration, established the width of the Pacific with precision for the first time in history.
One of the earliest voyages of scientific exploration was organized by Spain in the
Malaspina Expedition of 1789–1794. It sailed vast areas of the Pacific, from Cape Horn to Alaska, Guam and the Philippines, New Zealand, Australia, and the South Pacific.
File:Carta universal en que se contiene todo lo que del mundo se ha descubierto fasta agora hizola Diego Ribero cosmographo de su magestad, ano de 1529, en Sevilla.jpg, Made in 1529, the Diogo Ribeiro map was the first to show the Pacific at about its proper size
File:A compleat chart of the coast of Asia and America with the great South Sea - R.W. Seale del. et sculp. NYPL465242.tiff, Map of the Pacific Ocean during European Exploration, circa 1754.
File:Ortelius - Maris Pacifici 1589.jpg, Maris Pacifici by Ortelius (1589). One of the first printed maps to show the Pacific Ocean
File:A generall chart of the South Sea ... NYPL481132.tiff, Map of the Pacific Ocean during European Exploration, circa 1702–1707
New Imperialism
Growing
imperialism 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 of
HMS ''Beagle'' in the 1830s, with
Charles Darwin aboard;
HMS ''Challenger'' during the 1870s; the
USS ''Tuscarora'' (1873–76); and the German ''Gazelle'' (1874–76).
In Oceania, France obtained a leading position as imperial power after making
Tahiti and
New Caledonia protectorates in 1842 and 1853, respectively.
[Bernard Eccleston, Michael Dawson. 1998. ''The Asia-Pacific Profile''. Routledge. p. 250.] After navy visits to
Easter Island in 1875 and 1887, Chilean navy officer
Policarpo Toro negotiated the incorporation of the island into Chile with native
Rapanui in 1888. By occupying Easter Island, Chile joined the imperial nations.
[William Sater, ''Chile and the United States: Empires in Conflict'', 1990 by the University of Georgia Press, ] By 1900 nearly all Pacific islands were in control of Britain, France, United States, Germany, Japan, and Chile.
Although the United States gained control of
Guam and the Philippines from Spain in 1898,
Japan controlled most of the western Pacific by 1914 and occupied many other islands during the
Pacific War
The Pacific War, sometimes called the Asia–Pacific War or the Pacific Theatre, was the Theater (warfare), theatre of World War II fought between the Empire of Japan and the Allies of World War II, Allies in East Asia, East and Southeast As ...
; however, by the end of that war, Japan was defeated and the
U.S. Pacific Fleet was the virtual master of the ocean. The Japanese-ruled
Northern Mariana Islands came under the control of the United States. Since the end of World War II, many former colonies in the Pacific have become independent
states.
Geography

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 the
Antarctic region in the South to the
Arctic
The Arctic (; . ) is the polar regions of Earth, polar region of Earth that surrounds the North Pole, lying within the Arctic Circle. The Arctic region, from the IERS Reference Meridian travelling east, consists of parts of northern Norway ( ...
in the north.
The Pacific Ocean encompasses approximately one-third of the Earth's surface, having an area of larger than Earth's entire landmass combined, .
Extending approximately from the
Bering Sea
The Bering Sea ( , ; rus, Бе́рингово мо́ре, r=Béringovo móre, p=ˈbʲerʲɪnɡəvə ˈmorʲe) is a marginal sea of the Northern Pacific Ocean. It forms, along with the Bering Strait, the divide between the two largest landmasse ...
in the
Arctic
The Arctic (; . ) is the polar regions of Earth, polar region of Earth that surrounds the North Pole, lying within the Arctic Circle. The Arctic region, from the IERS Reference Meridian travelling east, consists of parts of northern Norway ( ...
to the northern extent of the circumpolar
Southern Ocean at
60°S (older definitions extend it to
Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. ...
's
Ross Sea), the Pacific reaches its greatest east–west width at about
5°N latitude, where it stretches approximately from Indonesia to the coast of
Colombiahalfway around the world, and more than five times the diameter of the Moon.
Its geographic center is in eastern
Kiribati south of
Kiritimati, just west from
Starbuck Island at . The lowest known point on Earththe
Mariana Trenchlies below sea level. Its average depth is , putting the total water volume at roughly .
Due to the effects of
plate tectonics, the Pacific Ocean is currently shrinking by roughly per year on three sides, roughly averaging a year. By contrast, the Atlantic Ocean is increasing in size.
Along the Pacific Ocean's irregular western margins lie many seas, the largest of which are the
Celebes Sea,
Coral Sea,
East China Sea (East Sea),
Philippine Sea,
Sea of Japan,
South China Sea (South Sea),
Sulu Sea,
Tasman Sea, and
Yellow Sea (West Sea of Korea). The
Indonesian Seaway (including the
Strait of Malacca and
Torres Strait) joins the Pacific and the
Indian Ocean to the west, and
Drake Passage and the
Strait of Magellan link the Pacific with the Atlantic Ocean on the east. To the north, the
Bering Strait connects the Pacific with the
Arctic Ocean.
As the Pacific straddles the
180th meridian, the ''West Pacific'' (or ''western Pacific'', near Asia) is in the
Eastern Hemisphere, while the ''East Pacific'' (or ''eastern Pacific'', near the Americas) is in the
Western Hemisphere.
The Southern Pacific Ocean harbors the
Southeast Indian Ridge crossing from south of Australia turning into the
Pacific-Antarctic Ridge (north of the
South Pole) and merges with another ridge (south of South America) to form the
East Pacific Rise which also connects with another ridge (south of North America) which overlooks the
Juan de Fuca Ridge.
For most of Magellan's voyage from the
Strait of Magellan to the
Philippines
The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...
, the explorer indeed found the ocean peaceful; however, the Pacific is not always peaceful. Many
tropical storms batter the islands of the Pacific. The lands around the
Pacific Rim are full of
volcano
A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.
On Earth, volcanoes are most oft ...
es and often affected by
earthquakes.
Tsunamis, caused by underwater earthquakes, have devastated many islands and in some cases destroyed entire towns.
The
Martin Waldseemüller map of 1507 was the first to show the Americas separating two distinct oceans. Later, the
Diogo Ribeiro map of 1529 was the first to show the Pacific at about its proper size.
Bordering countries
(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 (#).)
Asia-Pacific
* * (US)
*
*
*
*
* #
*
*
* * (France)
* * (US)
* * (People's Republic of China)
*
*
*
* * (People's Republic of China)
*
*
*
* * (France)
*
* #
* * (Australia)
* * (US)
*
*
*
*
* * (UK)
*
*
*
*
*
*
*
*
*
* * (New Zealand)
*
*
*
* * (France)
Americas
*
*
*
*
*
*
*
*
*
*
*
*
*
Uninhabited territories
Territories with no permanent civilian population.
* (US)
* (France)
* (Australia)
* (US)
* (US)
* (US)
* (US)
* (Australia)
* (US)
* (US)
* (US)
Landmasses and islands

The Pacific Ocean has most of the islands in the world. There are about 25,000 islands in the Pacific Ocean. The islands entirely within the Pacific Ocean can be divided into three main groups known as
Micronesia,
Melanesia and
Polynesia. Micronesia, which lies north of the equator and west of the
International Date Line, includes the
Mariana Islands in the northwest, the
Caroline Islands in the center, the
Marshall Islands to the east and the islands of
Kiribati in the southeast.
Melanesia, to the southwest, includes
New Guinea
New Guinea (; Hiri Motu: ''Niu Gini''; , fossilized , also known as Papua or historically ) is the List of islands by area, world's second-largest island, with an area of . Located in Melanesia in the southwestern Pacific Ocean, the island is ...
, the world's second largest island after
Greenland and by far the largest of the Pacific islands. The other main Melanesian groups from north to south are the
Bismarck Archipelago, the
Solomon Islands,
Santa Cruz,
Vanuatu,
Fiji
Fiji, officially the Republic of Fiji, is an island country in Melanesia, part of Oceania in the South Pacific Ocean. It lies about north-northeast of New Zealand. Fiji consists of an archipelago of more than 330 islands—of which about ...
and
New Caledonia.
The largest area,
Polynesia, stretching from
Hawaii
Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...
in the north to New Zealand in the south, also encompasses
Tuvalu,
Tokelau,
Samoa,
Tonga and the
Kermadec Islands to the west, the
Cook Islands,
Society Islands and
Austral Islands
The Austral Islands ( officially ''Archipel des Australes;'' ) are the southernmost group of islands in French Polynesia, an overseas country of France, overseas country of the France, French Republic in the Oceania, South Pacific. Geographicall ...
in the center, and the
Marquesas Islands,
Tuamotu,
Mangareva Islands, and
Easter Island to the east.
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 are
Bougainville, Hawaii, and the Solomon Islands.
The
coral 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 the
Great 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 include
Banaba (formerly Ocean Island) and
Makatea in the Tuamotu group of
French Polynesia.
File:Ladrilleros Beach Colombia.jpg, Ladrilleros Beach in Colombia on the coast of Chocó natural region
File:Tahuna maru islet Raroia.jpg, Tahuna maru islet, French Polynesia
File:Los Molinos.JPG, Los Molinos on the coast of Southern Chile
Water characteristics

The volume of the Pacific Ocean, representing about 50.1 percent of the world's oceanic water, has been estimated at some . Surface water temperatures in the Pacific can vary from , the freezing point of seawater, in the poleward areas to about near the equator.
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. The motion of Pacific waters is generally clockwise in the
Northern Hemisphere (the
North Pacific gyre) and counter-clockwise in the
Southern Hemisphere. The
North Equatorial Current, driven westward along
latitude 15°N by the
trade winds, turns north near the Philippines to become the warm Japan or
Kuroshio Current.
Turning eastward at about
45°N, the Kuroshio forks and some water moves northward as the
Aleutian Current, while the rest turns southward to rejoin the North Equatorial Current. The Aleutian Current branches as it approaches North America and forms the base of a counter-clockwise circulation in the
Bering Sea
The Bering Sea ( , ; rus, Бе́рингово мо́ре, r=Béringovo móre, p=ˈbʲerʲɪnɡəvə ˈmorʲe) is a marginal sea of the Northern Pacific Ocean. It forms, along with the Bering Strait, the divide between the two largest landmasse ...
. Its southern arm becomes the chilled slow, south-flowing
California Current. The
South Equatorial Current, flowing west along the equator, swings southward east of
New Guinea
New Guinea (; Hiri Motu: ''Niu Gini''; , fossilized , also known as Papua or historically ) is the List of islands by area, world's second-largest island, with an area of . Located in Melanesia in the southwestern Pacific Ocean, the island is ...
, turns east at about
50°S, and joins the main westerly circulation of the South Pacific, which includes the Earth-circling
Antarctic Circumpolar Current. As it approaches the Chilean coast, the South Equatorial Current divides; one branch flows around
Cape Horn and the other turns north to form the Peru or
Humboldt Current.
Climate

The climate patterns of the Northern and Southern Hemispheres generally mirror each other. The
trade 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 off
British Columbia
British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...
during the winter months due to the preferred flow of
ocean currents.
In the tropical and subtropical Pacific, the
El Niño Southern Oscillation (ENSO) affects weather conditions. To determine the phase of ENSO, the most recent three-month
sea surface temperature average for the area approximately to the southeast of
Hawaii
Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...
is computed, and if the region is more than above or below normal for that period, then an
El Niño or
La Niña is considered in progress.
In the tropical western Pacific, the
monsoon and the related
wet season during the summer months contrast with dry winds in the winter which blow over the ocean from the Asian landmass. 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 the
tropical cyclone basins are active.
The Pacific hosts the two most active
tropical 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, while
typhoons forming in the northwestern Pacific moving into southeast and east Asia from May to December. Tropical cyclones also form in the
South Pacific basin, where they occasionally impact island nations.
In the arctic, icing from October to May can present a hazard for shipping while persistent fog occurs from June to December. A climatological low in the Gulf of Alaska keeps the southern coast wet and mild during the winter months. The
Westerlies and associated
jet stream within the Mid-Latitudes can be particularly strong, especially in the Southern Hemisphere, due to the temperature difference between the tropics and Antarctica,
[John P. Stimac]
Air pressure and wind.
Retrieved on 8 May 2008. which records the coldest temperature readings on the planet. In the Southern hemisphere, because of the stormy and cloudy conditions associated with
extratropical 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.
Geology

The ocean was first mapped by
Abraham Ortelius; he called it Maris Pacifici following
Ferdinand 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.
The
andesite line is the most significant regional distinction in the Pacific. A petrologic boundary, it separates the deeper,
mafic igneous rock of the Central Pacific Basin from the partially submerged continental areas of
felsic igneous rock on its margins.
The andesite line follows the western edge of the islands off California and passes south of the
Aleutian arc, along the eastern edge of the
Kamchatka Peninsula, the
Kuril Islands, Japan, the
Mariana Islands, the
Solomon Islands, and New Zealand's
North Island.
The dissimilarity continues northeastward along the western edge of the
Andes
The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...
Cordillera 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 Pacific
Ring of Fire is the world's foremost belt of explosive
volcanism.
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 by
subduction zones. Only the central part of the North American coast and the Antarctic and Australian coasts have no nearby subduction zones.
Geological history
The Pacific Ocean was born 750million years ago at the breakup of
Rodinia, although it is generally called the
Panthalassa until the breakup of
Pangea, about 200million years ago.
The oldest Pacific Ocean floor is only around 180
Ma old, with older crust subducted by now.
Seamount chains
The Pacific Ocean contains several long
seamount chains, formed by
hotspot volcanism. These include the
Hawaiian–Emperor seamount chain and the
Louisville Ridge.
Economy
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
Petroleum, also known as crude oil or simply oil, is a naturally occurring, yellowish-black liquid chemical mixture found in geological formations, consisting mainly of hydrocarbons. The term ''petroleum'' refers both to naturally occurring un ...
and
natural gas are extracted, and
pearls are harvested along the coasts of Australia, Japan,
Papua New Guinea, Nicaragua, Panama, and the Philippines, although in sharply declining volume in some cases.
Fishing
Fish are an important economic asset in the Pacific. The shallower shoreline waters of the continents and the more temperate islands yield
herring,
salmon,
sardines,
snapper,
swordfish, and
tuna, as well as
shellfish.
Overfishing has become a serious problem in some areas. Overfishing leads to depleted fish populations and closed fisheries, causing both economic and ecologic consequences. For example, catches in the rich fishing grounds of the
Okhotsk Sea off the Russian coast have been reduced by at least half since the 1990s as a result of overfishing.
Environment

The Northwestern Pacific Ocean is most susceptible to micro plastic pollution due to its proximity to highly populated countries like Japan and China. The quantity of small plastic fragments floating in the north-east Pacific Ocean increased a hundredfold between 1972 and 2012. The ever-growing
Great Pacific Garbage Patch between California and Japan is three times the size of France. An estimated 80,000 metric tons of plastic inhabit the patch, totaling 1.8trillion pieces.
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.
The rivers then empty into the ocean, often also bringing chemicals used as
fertilizers in agriculture. The excess of oxygen-depleting chemicals in the water leads to
hypoxia and the creation of a
dead zone.
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.
In addition, the Pacific Ocean has served as the crash site of satellites, including
Mars 96,
Fobos-Grunt, and
Upper Atmosphere Research Satellite.
Nuclear waste

From 1946 to 1958,
Marshall Islands served as the
Pacific Proving Grounds, designated by the United States, and played host to a total of 67
nuclear tests conducted across various atolls. Several
nuclear weapons were lost in the Pacific Ocean, including one-megaton bomb that was lost during the
1965 Philippine Sea A-4 incident.
In 2021, the
discharge of radioactive water from the Fukushima nuclear plant into the Pacific Ocean over a course of 30 years was approved by the Japanese Cabinet. The Cabinet concluded the radioactive water would have been diluted to drinkable standard.
Apart from dumping,
leakage of tritium into the Pacific was estimated to be between 20 and 40 trillion
Bqs from 2011 to 2013, according to the Fukushima plant.
Deep sea mining
An emerging threat for the Pacific Ocean is the development of
deep-sea mining.
Deep-sea mining is aimed at extracting
manganese 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 the
Clarion 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.
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.
List of major ports
*
Acapulco
*
Auckland
Auckland ( ; ) is a large metropolitan city in the North Island of New Zealand. It has an urban population of about It is located in the greater Auckland Region, the area governed by Auckland Council, which includes outlying rural areas and ...
*
Bangkok
*
Busan
Busan (), officially Busan Metropolitan City, is South Korea's second list of cities in South Korea by population, most populous city after Seoul, with a population of over 3.3 million as of 2024. Formerly romanized as Pusan, it is the economi ...
*
Callao
*
Cebu City
*
Dalian
*
Guangzhou
Guangzhou, Chinese postal romanization, previously romanized as Canton or Kwangchow, is the Capital city, capital and largest city of Guangdong Provinces of China, province in South China, southern China. Located on the Pearl River about nor ...
*
Guayaquil
*
Haiphong
*
Ho Chi Minh City
*
Hong Kong
Hong Kong)., Legally Hong Kong, China in international treaties and organizations. is a special administrative region of China. With 7.5 million residents in a territory, Hong Kong is the fourth most densely populated region in the wor ...
*
Honolulu
*
Jakarta
*
Johor Bahru
*
Kaohsiung
*
Keelung
*
Long Beach
*
Los Angeles
Los Angeles, often referred to by its initials L.A., is the List of municipalities in California, most populous city in the U.S. state of California, and the commercial, Financial District, Los Angeles, financial, and Culture of Los Angeles, ...
*
Manzanillo
*
Manila
*
Manta
*
Melbourne
Melbourne ( , ; Boonwurrung language, Boonwurrung/ or ) is the List of Australian capital cities, capital and List of cities in Australia by population, most populous city of the States and territories of Australia, Australian state of Victori ...
*
Nagoya
*
Nakhodka
*
Oakland
*
Osaka
*
Panama City
*
Portland
*
San Diego
San Diego ( , ) is a city on the Pacific coast of Southern California, adjacent to the Mexico–United States border. With a population of over 1.4 million, it is the List of United States cities by population, eighth-most populous city in t ...
*
San Francisco
San Francisco, officially the City and County of San Francisco, is a commercial, Financial District, San Francisco, financial, and Culture of San Francisco, cultural center of Northern California. With a population of 827,526 residents as of ...
*
Seattle
Seattle ( ) is the most populous city in the U.S. state of Washington and in the Pacific Northwest region of North America. With a population of 780,995 in 2024, it is the 18th-most populous city in the United States. The city is the cou ...
*
Shanghai
*
Singapore
*
Sydney
*
Tianjin
*
Tokyo
*
Valparaíso
*
Vancouver
*
Vladivostok
*
Yokohama
is the List of cities in Japan, second-largest city in Japan by population as well as by area, and the country's most populous Municipalities of Japan, municipality. It is the capital and most populous city in Kanagawa Prefecture, with a popu ...
See also
*
Asia-Pacific Economic Cooperation
*
List of islands in the Pacific Ocean
*
*
List of rivers of the Americas by coastline#Pacific Ocean coast
*
List of ports and harbors of the Pacific Ocean
*
Pacific Alliance
*
Pacific coast
*
Pacific Time Zone
The Pacific Time Zone (PT) is a time zone encompassing parts of western Canada, the western United States, and western Mexico. Places in this zone observe standard time by subtracting eight hours from Coordinated Universal Time ( UTC−08:00 ...
*
Seven Seas
*
Trans-Pacific Partnership
*
War of the Pacific
*
Shackleton fracture zone
*
Natural delimitation between the Pacific and South Atlantic oceans by the Scotia Arc
References
Further reading
*
*
*
*
*
*
* Jones, Eric, Lionel Frost, and Colin White. ''Coming Full Circle: An Economic History of the Pacific Rim'' (Westview Press, 1993)
*
*
*
*
* Paine, Lincoln. ''The Sea and Civilization: A Maritime History of the World'' (2015).
*
* Samson, Jane. ''British imperial strategies in the Pacific, 1750–1900'' (Ashgate Publishing, 2003).
*
*
*
Historiography
* Calder, Alex, et al. eds. '' Voyages and Beaches: Pacific Encounters, 1769–1840'' (U of Hawai'i Press, 1999)
* Davidson, James Wightman. "Problems of Pacific history." ''Journal of Pacific History'' 1#1 (1966): 5–21.
*
* Dirlik, Arif. "The Asia-Pacific Idea: Reality and Representation in the Invention of a Regional Structure", ''Journal of World History'' 3#1 (1992): 55–79.
* Dixon, Chris, and David Drakakis-Smith. "The Pacific Asian Region: Myth or Reality?" ''Geografiska Annaler: Series B, Human Geography'' 77#@ (1995): 75+
* Dodge, Ernest S. ''New England and the South Seas'' (Harvard UP, 1965).
* Flynn, Dennis O., Arturo Giráldez, and James Sobredo, eds. ''Studies in Pacific History: Economics, Politics, and Migration'' (Ashgate, 2002).
* Gulliver, Katrina. "Finding the Pacific world." ''Journal of World History'' 22#1 (2011): 83–100
online* Korhonen, Pekka. "The Pacific Age in World History", ''Journal of World History'' 7#1 (1996): 41–70.
* Munro, Doug. ''The Ivory Tower and Beyond: Participant Historians of the Pacific'' (Cambridge Scholars Publishing, 2009).
* "Recent Literature in Discovery History." ''Terrae Incognitae'', annual feature in January issue since 1979; comprehensive listing of new books and articles.
* Routledge, David. "Pacific history as seen from the Pacific Islands." ''Pacific Studies'' 8#2 (1985): 81
online* Samson, Jane. "Pacific/Oceanic History" in
* Stillman, Amy Ku'uleialoha. "Pacific-ing Asian Pacific American History", ''Journal of Asian American Studies'' 7#3 (2004): 241–270.
External links
EPIC Pacific Ocean Data Collection Viewableon-line collection of observational data
NOAA In-situ Ocean Data Viewerplot and download ocean observations
NOAA PMEL Argo profiling floats Realtime Pacific Ocean dataNOAA TAO El 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
{{Authority control
Geography of Asia
Geography of North America
Geography of Oceania
Oceans surrounding Antarctica
Oceans
Geography of South America