There Are Five Oceans, Not Four: Complete List

The International Hydrographic Organization (IHO) and most nations recognize five oceans since 2000.

The Five Oceans

2000 IHO publication Limits of Oceans and Seas (3rd ed.) recognized Southern Ocean
Distinct circumpolar current (ACC), ecosystem, water mass
US (NOAA, NGIA), UK, Australia, others adopted; some holdouts remain
Previously: "Antarctic Ocean" or just southern extensions of P/A/I

P A I S A — Pacific, Atlantic, Indian, Southern, Arctic (by size)

Seas are subdivisions (Mediterranean, Caribbean, South China Sea). Some "seas" are larger than Arctic Ocean (e.g., Philippine Sea 5.7M km²).

South Pacific

Wanderlust World

Wanderlust World

#	Ocean	Area (km²)	% Earth Surface	Avg Depth (m)	Key Feature
1	Pacific	165,250,000	32%	4,280	Largest, deepest (Mariana Trench 11,034m), Ring of Fire
2	Atlantic	106,460,000	21%	3,646	S-shape; Gulf Stream; Mid-Atlantic Ridge
3	Indian	70,560,000	14%	3,741	Monsoon-driven; warmest; enclosed north
4	Southern (Antarctic)	20,327,000	4%	3,270	Circumpolar; ACC (largest current); 60°S boundary
5	Arctic	14,060,000	3%	1,205	Smallest, shallowest; sea ice; bordered by continents