Indian Ocean

Geography and physical characteristics

The Indian Ocean is the third-largest ocean by area. Much of its surface lies in the southern hemisphere. Average depths are several thousand metres, with the deepest point found in the Java Trench near the Sunda Islands (Java Trench / Sunda Islands), reaching roughly 7,500 metres. Its basin includes a variety of features such as continental shelves, submerged plateaus and deep trenches, and it connects to neighboring seas and gulfs through narrow straits and channels.

Marginal seas and notable bodies of water

Several important marginal seas, gulfs and passages form part of the ocean and support dense human populations along their shores:

• Bay of Bengal
• Arabian Sea
• Persian Gulf
• Red Sea

Climate, currents and ecosystems

The Indian Ocean is strongly influenced by the seasonal monsoon winds, which reverse direction between summer and winter and drive major surface currents. Those monsoons have shaped regional climates for millennia and affect rainfall on adjacent landmasses. The ocean supports rich marine ecosystems, including coral reefs, mangroves and productive fisheries, particularly along continental shelves and in upwelling zones.

Human uses, history and strategic importance

For centuries the Indian Ocean has been a corridor for trade and cultural exchange, linking ports from East Africa and the Arabian Peninsula to South and Southeast Asia and Australasia. Ancient and medieval maritime routes carried spices, textiles and other goods; in modern times the ocean hosts some of the world's busiest shipping lanes, including routes to the Suez Canal and through chokepoints that affect global energy supplies.

Resources and environmental challenges

The region is economically important for fisheries, hydrocarbons and mineral resources on and beneath the seabed. At the same time it faces environmental pressures: overfishing, coastal development, pollution and warming-driven coral bleaching are widespread concerns. Efforts by littoral states, regional organizations and international partners aim to improve management of resources and protect vulnerable habitats.

Notable facts: The Indian Ocean is the world’s third-largest ocean, contains extensive marginal seas such as the Bay of Bengal and the Arabian Sea, and plays a key role in global climate and commerce.