The average depth of the oceans is about 4 km. More precisely the average depth is 3,688 meters (12,100 ft). Nearly half of the world’s marine waters are over 3,000 meters (9,800 ft) deep. “Deep ocean,” which is anything below 200 meters (660 ft.), covers about 66% of Earth’s surface. This figure does not include seas not connected to the World Ocean, such as the Caspian Sea.View More depth of oceans
Oceanographers usually divide ocean waters into separate layers, called zones, from the surface all the way to the seafloor. Zones are based on the amount of sunlight that can penetrate the water’s layers and have appropriate names: the sunlight zone, the twilight zone, and the midnight zone. We know most about the upper layers of the ocean, because that’s where humans are most able to explore. Those layers are also where most sea life can be found.View More what is below the Surface of the ocean?