American Oceans

10 Largest Oceans and Seas on Earth

The Earth’s surface comprises about 71% water, with continents and islands covering the remaining part. To understand how vast water bodies are, you may consider looking into the sizes of various oceans and seas. Which is the largest, how deep are they, and how critical are they to the planet’s sustainability? 

biggest oceans

This article explores ten of the world’s largest oceans and seas, including the Pacific Ocean, Mediterranean Sea, Atlantic Ocean, Caribbean Sea, and Indian Ocean. You’ll also discover their deepest point, the marine life available, their economic purposes, and more. Below is a list of how we’ve ranked the world’s most extensive oceans and seas, including their area, average depth, and deepest point.

Pacific Ocean

Area: 165,250,000 square kilometers

Deepest Point: Challenger Deep (36,070 feet)

Pacific Ocean

The Pacific Ocean basin covers approximately 1/3 of the Earth’s surface, making up about 46% of the water surface globally. It’s, therefore, the largest ocean in the world. Its average depth is 4,280 m, with the deepest point being Challenger Deep, which descends to 10,994 meters (36,070 feet). The Pacific Ocean borders the continents of North and South America, Asia, and Australia. Ferdinand Magellan, a Portuguese explorer, named this massive water body “Pacific” in 1520, meaning “peaceful.” The Pacific Ocean is the oldest of all existing oceans. According to the National Ocean Service, the oldest rock in this ocean dates back about 200 million years. The ocean basin is home to about 25,000 islands and over 228450 species, including hammered sharks, elephant seals, killer whales, penguins, and sea slugs. The Pacific Ocean has numerous shipping routes that connect the bordering continents, oceans, and seas.

Atlantic Ocean

Area: 106,460,000 square kilometers

Deepest Point: Milwaukee Deep (27,493 feet)

Atlantic Ocean

The Atlantic Ocean basin is the 2nd biggest ocean in the world, covering about 20% of the Earth’s surface. The ocean borders various countries in America, Europe, and Africa. The average depth of the Atlantic is 3,646 m, with the deepest part being Milwaukee Deep, which descends to around 8,380 m. The Atlantic Ocean derives its name from Greek mythology’s “Sea of Atlas.” It’s roughly 135 million years old, having formed during the Cretaceous period. The dreaded Bermuda Triangle (“the Devil’s Triangle”) lies in this ocean. This Triangle has mysteriously led to the disappearance of many ships and airplanes. The Panama Canal connects the Atlantic Ocean to the Pacific Ocean. The Atlantic is home to many seas, islands, gulfs, and bays. It has over 17,500 species, including sharks, manatees, sea turtles, and humpback whales.

Indian Ocean

Area: 70, 560,000 square kilometers

Deepest Point: Sunda Trench (23,920 feet)

the Indian ocean

The Indian Ocean basin makes up about 19.8% of the planet’s water and falls in the third position after the Atlantic and Pacific oceans. It borders several countries in East Africa, Asia, and western Australia. The average depth of this ocean is 3,741 m, deeper than the Atlantic Ocean. Its deepest point is the Sunda Trench, descending to approximately 7,290 m. With an average temperature of 77°F, the Indian Ocean takes the lead as the warmest ocean in the world. This ocean is relatively calm and offers significant sea routes for transporting materials such as oil, rice, sugar, and silk. However, a devastating tsunami in 2004 led to the loss of over 200,000 deaths and the massive destruction of property. The Indian Ocean is home to several islands, including Madagascar (4th largest island globally). It offers a suitable habitat for over 9,000 species, including dugongs, whales, sea snakes, sharks, and turtles.

Southern Ocean

Area: 20,327,000

Deepest Point: Factorian Deep (24389 feet)

Southern Ocean Antarctica

The Southern Ocean basin (Antarctic Ocean) encircles Antarctica and extends to parts of the Atlantic, Pacific, and Indian Oceans. As the planet’s 4th largest ocean, the Southern Ocean has an average depth of 3,270 m. Its deepest point is the Factorian Deep which stretches to 7,434 m below sea level.   The Southern Ocean is geologically the world’s youngest ocean. It was formed about 34 million years ago when South America and Antarctica separated. Climate change, pollution, fishing, and hunting have affected the fragile ecosystem of the Antarctic Ocean. While the Southern Ocean is home to over 9,000 species, most are near extinction. You can still find creatures such as seals, penguins, and whales.

Arctic Ocean

Area: 14,060,000 square kilometers

Deepest Point: Molloy Deep (18208 feet)

Arctic Ocean

The Arctic Ocean basin is the world’s smallest, shallowest, and coldest ocean, making up 4.3% of global water. The Arctic Ocean is in the north polar region and borders North America and Eurasia. Its average depth is 1,038 m, with Molloy Deep (its deepest point) descending to about 5,550 m. The Arctic Ocean formed during the Cretaceous Period, about 145-65 million years ago. Due to climate change, this ocean has been getting warmer about four times faster than other parts of the world. This puts its vulnerable ecosystem at risk, including people living nearby. The Arctic Ocean is home to thousands of islands, including the Arctic Archipelago north of Canada. Despite the vast ice in the Arctic Ocean, you can find over 5,500 animal species adapted to the cold habitats.

Coral Sea

Area: 4,791,000 square kilometers

Deepest Point: Bougainville (29,986 feet)

coral sea

The Coral Sea is located southwest of the Pacific Ocean and is surrounded by Australia, New Guinea, New Caledonia, Solomon Islands, and New Hebrides. The average depth of this sea is 2,394 m, with its deepest point in Bougainville measuring 9,140 m below sea level. The name “Coral” came from the numerous coral reefs, including the world’s largest known as the Great Barrier Reef. Geologists say the Coral Sea began forming 48-58 million years ago. The sea is warm, calm, and with occasional cyclones. Its natural beauty makes it a popular tourist destination. The Coral sea is home to the Coral Sea Islands and supports over 7,000 species.

Arabian Sea

Area: 3,862,000 Square Kilometers

Deepest Point: Wheatley Deep (19,028 feet)

the arabian gulf seascape

The Arabian Sea is part of the northern Indian Ocean and sits between the Arabian Peninsula, India, the Gulf of Oman, Pakistan, and Iran. On the western side is the Gulf of Aden, which connects this sea to the Red Sea. The Arabian Sea has an average depth of 2,734 m, with its deepest point in Wheatley Deep descending to about 5,800 m. The formation of this sea took place roughly 50 million years ago. Throughout history, the Arabian Sea served as an essential water body for numerous seaports and trade routes. The sea is home to several islands, including Lakshadweep Islands, Astola Island, Socotra, and Masirah. It’s home to over 1,769 species, including whales, sharks, sardines, tuna, sea turtles, and wahoo.

South China Sea

Area: 3,685,000 Square Kilometers

Deepest Point: China Sea Basin (16,456 feet)

South China Sea

The South China Sea sits between South China, Indochinese Peninsula, the Philippines, and several islands. Its average depth is 1,212 m, and the deepest point in the China Sea Basin descends to around 5,016 m. Below the South China Sea is the submerged continental shelf near the Philippine islands. This sea began forming around 45 to 17 million years ago, leaving a V-shaped basin. Over the years, rivers such as the Mekong, Pearl, and Red Rivers have deposited large sediments, oil, and gasses. The sea has shipping routes where about 33.33% of the world’s shipping takes place. The South China Sea has over 200 islands, some of which stay submerged. It’s also home to over 3,000 fish species and 600 types of coral reefs.

Caribbean Sea

Area: 2,754,000 Square Kilometers

Deepest Point: Cayman Trough (25,216 feet)

Caribbean Sea

The Caribbean Sea is part of the western Atlantic Ocean, located between Central America, Mexico, Greater Antilles, Lesser Antilles, and Cuba. The Caribbean Sea region, including islands and adjacent coasts, is known as the “Caribbean.” This sea has an average depth of 2,200 m, with the deepest point in Cayman Trough descending to 7,686 m. The formation of the Caribbean Sea dates back around 160 and 180 million years. This sea has a rich history of exploration, especially by Christopher Columbus. Transport and trading activities across this sea attracted pirates in the 1560s. Today, this sea’s abundance of sunshine attracts numerous tourists year-round. The Caribbean Sea is home to 22 islands and over 1,400 species of marine mammals, fish, and coastal mangroves.

Mediterranean Sea

Area: 2,500,000 Square Kilometers

Deepest Point: Calypso Deep (17,280 feet)

Mediterranean Sea

The Mediterranean sea covers 0.7% of the planet’s ocean surface, making it one of the largest seas globally. It lies between Western and Eastern Europe, Anatolia, North Africa, and the Levant. Its average depth of 1,500 m, with its deepest point in Calypso Deep descending to 5,267 m. The Strait of Gibraltar (a narrow waterway) connects the Mediterranean Sea with the Atlantic Ocean. The Mediterranean Sea formed about 5.9 million years ago when it cut off from the Atlantic Ocean. This sea was an important trade route for merchants in ancient times. Today, large coastal populations, pollution, and intense fishing are the primary concerns in this sea. Several islands dot the Mediterranean Sea, some of which formed through volcanic eruptions. The Mediterranean is home to over 17,000 marine species, including 712 species of fish.

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