What is the largest ocean?
Quick answer
The Pacific Ocean is the largest ocean on Earth, covering about 165 million km² (64 million sq mi), roughly one-third of the planet’s surface. It’s bigger than all the land on Earth combined and holds about half of the world’s ocean water. It’s also the deepest ocean, home to the Mariana Trench.
Key facts
- Area
- About 165 million km² (64 million sq mi)
- Average depth
- About 4,000 m (13,000 ft)
- Deepest point
- Challenger Deep, about 10,935 m
- Named by
- Ferdinand Magellan, 1520
The five oceans compared
| Rank | Ocean | Area (approx.) | Share of world ocean |
|---|---|---|---|
| 1 | Pacific | 165 million km² | ~46% |
| 2 | Atlantic | 106 million km² | ~23% |
| 3 | Indian | 70 million km² | ~20% |
| 4 | Southern | 21 million km² | ~6% |
| 5 | Arctic | 15 million km² | ~4% |
The Southern Ocean around Antarctica was officially recognized by many geographers and by National Geographic in 2021, making five oceans instead of four. Some figures vary depending on where boundaries are drawn.
How the Pacific got its name
Portuguese explorer Ferdinand Magellan sailed into it in 1520 after a stormy passage around South America. The water seemed so calm that he named it Mar Pacífico, the “peaceful sea.” It isn’t always peaceful: the Pacific produces powerful typhoons and most of the world’s tsunamis.
The Ring of Fire
Around the edges of the Pacific lies the Ring of Fire, a horseshoe of volcanoes and earthquake zones where tectonic plates meet. About 75% of Earth’s active volcanoes are found there, and its earthquakes trigger most of the world’s tsunamis; see where the word tsunami comes from.
The deepest place on Earth
The Pacific contains the Mariana Trench, where the Challenger Deep plunges nearly 11 km down; see where the Mariana Trench is.
Shrinking ocean
The Pacific is slowly getting smaller, by a few centimeters a year, as plates slide beneath its edges, while the Atlantic is widening. Hundreds of millions of years ago, the continents formed one landmass surrounded by a single ocean, Panthalassa; see what Pangaea was.
To learn why the oceans matter, read why the ocean is important.
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