Deepest Oceans in the World: All 5 Ranked by Maximum Depth

The world's five oceans cover over 71% of Earth's surface and contain 97% of the planet's water. While most people know the Pacific is the largest, fewer realize just how deep our oceans go -- the deepest point plunges nearly 11 kilometers below the surface. Here are all five oceans ranked by their maximum depth.

All 5 Oceans Ranked by Depth

The Pacific Ocean: Earth's Deepest and Largest

The Pacific Ocean is not just the deepest ocean -- it is also the largest, covering approximately 165.25 million km² (more than all of Earth's land area combined). Its deepest point, Challenger Deep in the Mariana Trench, sits 10,994 meters (36,070 feet) below sea level. If Mount Everest were placed in Challenger Deep, its peak would still be more than 2,000 meters underwater.

The Mariana Trench is located near the Mariana Islands in the western Pacific. It was formed by the subduction of the Pacific Plate beneath the smaller Mariana Plate. Only four people have ever reached the bottom: Jacques Piccard and Don Walsh in 1960 aboard the Trieste, filmmaker James Cameron in 2012, and explorer Victor Vescovo in 2019.

The Atlantic Ocean: Second Deepest

The Atlantic Ocean's deepest point is the Puerto Rico Trench at 8,376 meters. This trench sits at the boundary between the Caribbean and North American tectonic plates and stretches about 800 km long. The Atlantic is the second-largest ocean at 106.46 million km² and is notable for the Mid-Atlantic Ridge, a massive underwater mountain range that runs roughly down the center of the ocean from north to south for over 16,000 km.

The Indian Ocean: Third Deepest

The Indian Ocean reaches its greatest depth at the Sunda Trench (also called the Java Trench) at 7,450 meters, located south of Indonesia. It is the world's third-largest ocean at 70.56 million km² and the warmest ocean overall. The Indian Ocean is geologically active -- the 2004 earthquake along the Sunda Trench generated a devastating tsunami that affected 14 countries.

The Southern Ocean and Arctic Ocean

The Southern Ocean, officially recognized by the International Hydrographic Organization in 2000, surrounds Antarctica and reaches 7,236 meters at the South Sandwich Trench. It is the fourth-deepest and plays a critical role in global ocean circulation through the Antarctic Circumpolar Current, the strongest ocean current on Earth.

The Arctic Ocean is the shallowest and smallest ocean, with a maximum depth of 5,450 meters at Molloy Deep (located west of Svalbard) and an average depth of only 1,205 meters. Much of the Arctic is covered by sea ice, though coverage has decreased dramatically due to climate change -- losing about 13% per decade since satellite measurements began in 1979.

Ocean Trenches: How They Form

The deepest points in each ocean are found at subduction zones, where one tectonic plate is forced beneath another. As the denser oceanic plate dives into the mantle, it creates a deep trench on the ocean floor. These trenches are geologically active zones associated with earthquakes and volcanic activity. The "Ring of Fire" around the Pacific Ocean contains most of the world's deepest trenches.

Key Facts

• The Mariana Trench (10,994m) is the deepest point on Earth -- deeper than Everest is tall.
• The average depth of all oceans combined is about 3,688 meters.
• More than 80% of the ocean floor remains unmapped and unexplored.
• The Pacific Ocean alone covers more area than all land on Earth combined.
• The Arctic Ocean is roughly 5 times smaller than the Pacific.
• Ocean pressure at Challenger Deep is over 1,000 times atmospheric pressure at sea level.

Fun Facts

• More people have walked on the Moon (12) than have visited Challenger Deep (4).
• The Mid-Atlantic Ridge is the longest mountain range on Earth at over 16,000 km -- all of it underwater.
• Sound travels about 4.5 times faster in water than in air.
• If all the ice in the Arctic Ocean melted, global sea levels would not rise significantly because the ice is already floating and displacing water.
• The Mariana Trench was found to contain microplastic pollution even at its deepest point.

Final Thoughts

Our oceans remain Earth's last great frontier. Despite covering more than two-thirds of the planet, the vast majority of the ocean floor is still unmapped. From the crushing pressures of Challenger Deep to the icy shallows of the Arctic, ocean depth shapes marine ecosystems, global climate, and tectonic activity in ways we are only beginning to understand.