The Indian Ocean gyre is composed of two major currents: the South Equatorial Current, and the West Australian Current. Normally moving counter-clockwise, in the winter the Indian Ocean gyre reverses direction due to the seasonal winds of the South Asian Monsoon.

Since there are very few subduction zones in the Atlantic, Indian and Arctic oceans, these basins are expanding due to seafloor spreading.

The Indian Ocean's average depth is 12,274 feet (3,741 metres), and its deepest point, in the Sunda Deep of the Java Trench off the southern coast of the island of Java (Indonesia), is 24,442 feet (7,450 metres).

The ocean formed billions of years ago. Water remained a gas until the Earth cooled below 212 degrees Fahrenheit . At this time, about 3.8 billion years ago, the water condensed into rain which filled the basins that we now know as our world ocean.