Earth's Five Oceans: Ranked by Size

The International Hydrographic Organization (IHO) recognizes five oceans, listed here by surface area:

1. Pacific Ocean – 165.2M km² (46% of Earth's water surface; larger than all land combined).
2. Atlantic Ocean – 106.5M km² (separates Americas from Europe/Africa).
3. Indian Ocean – 70.6M km² (bounded by Africa, Asia, Australia, Southern Ocean).
4. Southern (Antarctic) Ocean – 20.3M km² (waters south of 60°S; recognized 2000).
5. Arctic Ocean – 14.1M km² (smallest, shallowest, largely ice-covered).

Key Distinctions

• Pacific holds the Mariana Trench (deepest point: 10,984 m).
• Atlantic is saltiest on average (3.5–3.7%).
• Southern Ocean is defined by the Antarctic Circumpolar Current, not just latitude.
• Arctic is technically a mediterranean sea of the Atlantic, but treated as an ocean for its distinct ecosystem and sea-ice regime.

Together they cover 71% of Earth's surface and contain 97% of its water.