Which ocean is the deepest?

The Pacific Ocean is the deepest ocean on Earth.

Its deepest known point is Challenger Deep, within the Mariana Trench in the western Pacific. Measurements place the seafloor there at roughly 10,900 metres below sea level, deeper than Mount Everest is tall. The extreme depth results from one tectonic plate being forced beneath another at a subduction zone.

The Pacific is also the largest ocean basin, extending between Asia and Australia on the west and the Americas on the east. Its floor contains many trenches, volcanic arcs, and earthquake zones, forming much of the tectonically active “Ring of Fire.”

A common mix-up is treating “deepest ocean” as the same as “largest ocean.” In this case the Pacific holds both records, but the Atlantic, Indian, and Arctic oceans each have their own deepest trenches. Depth figures can vary slightly because sonar surveys and reference standards are continually refined.