The Five Major Oceans: Complete Guide

Earth's Five Ocean Basins

The International Hydrographic Organization (IHO) recognizes five oceans (2000):

1. Pacific Ocean – Largest (165.2M km², 46% of water surface). Arctic to Southern Ocean. Americas to Asia/Australia. Deepest (Mariana Trench).
2. Atlantic Ocean – 2nd (106.4M km²). Americas to Europe/Africa. Includes Caribbean, Mediterranean, Baltic.
3. Indian Ocean – 3rd (70.5M km²). Africa to Australia, north to India. Monsoon-driven.
4. Southern (Antarctic) Ocean – 4th (20.3M km²). Encircles Antarctica to 60°S. Unique circumpolar current.
5. Arctic Ocean – Smallest (14.1M km²). North Pole, surrounded by continents. Seasonal ice cover.

Key Distinctions

• Pacific = largest, deepest, most islands.
• Atlantic = busiest trade routes, strong meridional overturning.
• Indian Ocean = warmest, monsoon-dominated.
• Southern = only ocean unbroken by continents, drives global circulation.
• Arctic = shallowest, most ice-covered, fastest warming.

All are interconnected—one world ocean.