The Indian Ocean covers about 14% of the Earth’s surface area. This ocean region is enclosed on three sides by the landmasses of Africa, Asia, and Australia.
The Indian Ocean's southern border is open to water exchange with the much colder Southern Ocean. Average depth of the Indian Ocean is 3,900 meters (12,800 feet).
The deepest point in this ocean region occurs in the Java Trench with a depth of 7,258 meters (23,812 feet) below sea level.
The Indian Ocean region has relatively few islands. Continental shelf areas tend to be quite narrow and not many shallow seas exist.
Relative to the Atlantic Ocean, only a small number of streams drain into the Indian Ocean. Consequently, the surface area of the Indian Ocean is approximately 400% larger than the land area supplying runoff into it.
Some of the major rivers flowing into the Indian Ocean include the Zambezi, Arvandrud/Shatt-al-Arab, Indus, Ganges, Brahmaputra, and the Irrawaddy.
Seawater salinity ranges between 32 and 37 parts per 1000. Because much of the Indian Ocean lies within the tropics, this basin has the warmest surface ocean temperatures.