The Top 5 Largest Seas on Earth

  Name Surface Area
Water Volume
Deepest depth
1 Philippine Sea 5,688,163 5,718,199 24,785,853 10,061
2 Arabian Sea 4,237,083 4,242,174 13,908,640 5,864
3 Coral Sea 4,026,898 4,036,241 10,059,264 9,055
4 Tasman Sea 3,346,649 3,353,534 11,297,474 6,601
5 South China Sea 3,309,289 3,315,500 4,247,615 5,315
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 Special Report

What's the Difference Between an Ocean and a Sea Anyway?

Good question. If you do a search on the internet for "largest sea" you'll find most pages mix the two. At we know there is a difference between a sea and an ocean, although a small one. The National Oceanic and Atmospheric Administration explains it this way:

"Many people use the terms "ocean" and "sea" interchangeably when speaking about the ocean, but there is a difference between the two terms when speaking of geography (the study of the Earth's surface).

Seas are smaller than oceans and are usually located where the land and ocean meet. Typically, seas are partially enclosed by land." (A.)

The Philippine Sea is the Largest Sea on Earth

The Philippine Sea is so big that the world's largest volcano was recently discovered in it in 2019. The Apolaki Caldera, an undersea crater formed after a volcano erupted there eons ago, is 150 kilometres in diameter and is down over -2,500 meters under the sea.

The Philippine Sea itself is located in the western North Pacific Ocean, just east and north of the Philippines. It has a surface area of 5,688,163 km2 (18,661,952 feet), and is also extremely deep at 10,061 metres (33,000 feet). That's impressive when you consider that the deepest part of any ocean on earth is the Challenger Deep in the Mariana Trench, which is 11,000 metres deep (36,200 feet).

Probably The Richest Ecosystem on The Planet That We're Messing Up

The average depth of the Philippine Sea is 6,000 metres (19,700 feet). It's a sea because it's surrounded by a large chain of islands. The area is one of the richest marine ecosystems on earth, especially when it comes to coral reefs. Its biodiversity is astounding and precious, but, the bad news is, like other oceans and seas on Earth, we humans are leaving our mark. The good news is that there are people who care about the Philippine Sea and are trying to protect the reefs and all the marine life in them.

The Arabian Sea, an Ancient Route of Trade and Commerce

Sitting on top of the northwestern Indian Ocean and surrounded by countries steeped in the world's ancient history, the Arabian Sea shares coastline with Pakistan, India, Iran, Oman, Yemen, the Maldives and Somalia. The Arabian Sea is the second largest sea in the world and thus makes it number 2 on our top 5 list of the world's largest seas with over 4 million square kilometres of surface water.

Since ancient times leading up to today, the Arabian Sea has been a vital route of trade and commerce since the dawn of civilization. Today it has some of the world's busiest shipping lanes and important port cities such as Karāchi in Pakistan. The Arabian Sea has also appeared in one of the most important Arabic literary works of all time, as Sinbad from One Thousand and One Nights has sailed its legendary waters (we think that's pretty cool).

The natural ecosystem and biodiversity of the Arabian Sea are rich and varied, however since it is an important trade route for oil and gas and other industries such as fishing, marine habitats and wildlife are increasingly subject to ecological human pressures which have lead to environmental damage caused by pollution or overfishing.

Maybe Donate to a Worthy Cause

If you really, really care about sea life and the health of all our oceans and seas, maybe head on over to Oceana , another superhero organization fighting the good fight, and maybe hit them up with a nice donation. Every little bit helps.

By the way, in case you're wondering, here are the Top 5 Smallest Seas on Earth.

Noel James Riggs

Noel James Riggs,
Owner and Head Writer, Top 5 of
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Top 5 Special Reports Sources:
A. NOAA. (2020). What's the difference between an ocean and a sea?

Tags: Planet Earth, Water, Threatened & Endangered Species, Top 5 Largest, The Environment

Sources:  Environmental Science & Technology Vol 44. No 10. “Surface Area and the Seabed Area, Volume, Depth, Slope, and Topographic Variation for the World’s Seas, Oceans, and Countries" (PDF)

List Notes: Data is the top 5 largest seas on Earth. For the purposes of this list, a sea is defined as a part of the ocean partially enclosed by land.
Largest Seas on Earth

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