The ten largest seas on Earth by total surface area, from the vast Philippine Sea down to the Sea of Okhotsk.
Quick answer: 1. Philippine Sea, 2. Coral Sea, 3. Arabian Sea, 4. South China Sea, 5. Caribbean Sea, 6. Mediterranean Sea, 7. Bering Sea, 8. Bay of Bengal, 9. Gulf of Mexico, 10. Sea of Okhotsk.
Seas are large bodies of saltwater that are partially enclosed by land or connected to an ocean. This list ranks the ten largest seas by total surface area, covering the Pacific, Atlantic, Indian, and Arctic basins. It's a quick reference for geography students, map enthusiasts, and anyone curious about the scale of Earth's marginal seas. The ranking runs from largest to smallest, so rank 1 is the sea with the greatest area.
The largest sea on Earth, covering roughly 5.7 million km² of the western Pacific Ocean. It is bounded by the Philippines, Taiwan, Japan, and the Mariana Trench — home to the deepest point on Earth.
The second-largest sea, lying off the northeast coast of Australia. It contains the Great Barrier Reef, the world's largest coral reef system, and spans more than 700,000 km² of protected marine park.
The largest sea in the Indian Ocean basin, stretching between the Arabian Peninsula and India. It is a critical maritime trade route and supports one of the world's most important fishing grounds.
The largest marginal sea in the western Pacific after the Philippine Sea, covering about 3.5 million km². It is one of the world's busiest shipping corridors and contains the Spratly and Paracel Islands.
The largest sea in the Atlantic Ocean basin, bounded by Central America, South America, and the Caribbean island arc. It is known for its tropical climate, coral reefs, and hurricane activity.
The largest inland sea in the world, connected to the Atlantic Ocean via the Strait of Gibraltar. It is nearly enclosed by Southern Europe, North Africa, and Western Asia, and its history spans thousands of years of civilization.
The northernmost of the large seas, separating Alaska from Russia's Kamchatka Peninsula. It is rich in marine life and supports one of the world's largest fisheries, particularly for pollock.
The largest bay in the world, often classified as a sea. It lies between India and Myanmar and is fed by the Ganges, Brahmaputra, and Meghna rivers — the largest river delta system on Earth.
The largest gulf in the world, bordered by the United States, Mexico, and Cuba. It is a major basin for oil and natural gas production and is prone to powerful hurricanes.
The smallest sea on this list, bounded by Russia's Kamchatka Peninsula, the Kuril Islands, and the island of Hokkaido, Japan. It is one of the coldest seas in the world and freezes over in winter.
| # | Name | oceanBasin | avgDepth | maxDepth |
|---|---|---|---|---|
| 1 | Philippine Sea | Pacific Ocean | 6,000 m | 10,994 m (Mariana Trench) |
| 2 | Coral Sea | Pacific Ocean | 2,400 m | 9,140 m (Bougainville Trench) |
| 3 | Arabian Sea | Indian Ocean | 2,700 m | 4,652 m |
| 4 | South China Sea | Pacific Ocean | 1,200 m | 5,016 m |
| 5 | Caribbean Sea | Atlantic Ocean | 2,200 m | 7,686 m (Cayman Trench) |
| 6 | Mediterranean Sea | Atlantic Ocean | 1,500 m | 5,267 m (Calypso Deep) |
| 7 | Bering Sea | Pacific Ocean | 1,600 m | 4,096 m |
| 8 | Bay of Bengal | Indian Ocean | 2,600 m | 4,694 m |
| 9 | Gulf of Mexico | Atlantic Ocean | 1,600 m | 4,384 m (Sigsbee Deep) |
| 10 | Sea of Okhotsk | Pacific Ocean | 860 m | 3,374 m |
Seas are ranked by total surface area in square kilometers, using figures from the International Hydrographic Organization (IHO) limits as compiled in Wikipedia's "List of seas" and cross-checked against the National Oceanic and Atmospheric Administration (NOAA) and Encyclopaedia Britannica. Marginal seas, inland seas, and large gulfs are included if they are recognized as seas by the IHO. The ranking runs from largest to smallest, so rank 1 has the greatest area. Areas are rounded to the nearest 1,000 km² as reported by the sources.
The Philippine Sea is the largest sea in the world, with a total surface area of about 5.7 million km². It lies in the western Pacific Ocean and contains the Mariana Trench, the deepest point on Earth.
Seas are smaller than oceans and are typically partially enclosed by land, while oceans are the vast, interconnected bodies of water that cover most of the planet. Seas are often located at the margins of oceans.
No. The Caspian Sea is classified as a lake, not a sea, because it is entirely enclosed by land with no natural connection to the global ocean. It is the largest lake in the world by surface area.
The Philippine Sea is the deepest, reaching 10,994 m (6.8 miles) at the Challenger Deep in the Mariana Trench, the deepest known point in any ocean or sea on Earth.