Home › Water › Oceans & Seas
Indian Ocean
The world's third-largest and warmest ocean
The Indian Ocean is the third-largest, about 70.6 million square kilometers (27.2 million square miles), bounded by Africa to the west, Asia to the north, and Australia to the east. Unlike the Pacific and Atlantic, it is closed off in the north by the Asian landmass, and that geography gives it a unique character: it is the warmest of the great oceans, and its northern reaches drive the monsoon winds on which billions of people depend for rain.
Its deepest point lies in the Sunda (Java) Trench, about 7,290 meters (23,920 feet) down, where the Indian Plate dives beneath Southeast Asia — a boundary capable of the catastrophic 2004 earthquake and tsunami. The ocean cradles strategic waterways and chokepoints such as the Strait of Hormuz and the Strait of Malacca, through which much of the world's oil and trade passes, and scatters coral archipelagos like the Maldives and Seychelles across its tropical heart.
The Indian Ocean was the cradle of some of history's earliest long-distance sea trade, its predictable monsoon winds carrying merchants between Africa, Arabia, India, and the Far East for thousands of years. Today it is warming faster than any other ocean basin, with consequences for monsoon rainfall and the hundreds of millions who live along its rim.