Which sea is the largest by area?

Which sea is the largest by area? The Philippine Sea is the world's largest sea, covering roughly 5.7 million square kilometres.

It is a marginal sea of the western Pacific, lying east of the Philippines and extending toward Japan, Taiwan, the Mariana Islands and Micronesia. Its floor rests largely on the Philippine Sea Plate, a complex tectonic region marked by deep trenches, including the Mariana Trench and the Philippine Trench.

A common mix-up is the South China Sea, which is also enormous and lies west of the Philippines. However, the Philippine Sea is larger by area. The Coral Sea, northeast of Australia, is another major Pacific sea but ranks below it. Exact area figures vary slightly because geographers use different boundaries for marginal seas.

The Philippine Sea is also exceptionally deep and tectonically active. Its trenches and island arcs formed through subduction, where one tectonic plate sinks beneath another. That setting contributes to powerful earthquakes, volcanic activity and some of the deepest seafloor on Earth.