Smallest sea
Who
Sea of Marmara
What
11,350 square kilometre(s)
Where
Türkiye ()

The Sea of Marmara is the smallest true sea in the world. It is only 175 miles (280 km) long and around 50 miles (80 km) wide at its widest point. The total surface area is only 4,382 square miles (11,350 square km), with an average depth of 1,620 ft (494 m) and a maximum depth of 4,446 ft (1,355 m) in the centre. It is located in Turkey and connects the Black Sea through the Bosporus to the Aegean Sea through the Dardanelles.


Seas are smaller bodies of water than oceans, but still large water bodies, partly enclosed by a land mass and connected to an ocean.

The largest of the Earth’s seas is the South China Sea at around 3,500,000 square kilometres (1,400,000 square miles), and it borders China, Philippines, Malaysia, Brunei, Indonesia, Singapore and Vietnam. Often a source of contested ownership, the sea is home to thousands of islands and adopted its current shape around 17 million years ago.