What’s the difference between a sea and an ocean?

Have you ever wondered how a sea is different to an ocean? The two are often used interchangeably, but they have many differences.

Differences between an ocean and a sea

Oceans are bigger than seas. They cover 70% of the planet and have an average depth of 3800m.

Oceans are not contained by land. Seas are fully or partially enclosed.

Oceans are generally deeper than seas.

Ocean currents affect the climate around the world.

How many oceans are there?

There are five oceans — the Pacific, Atlantic, Southern, Indian and Arctic. Although the oceans are split into five distinct areas, they are not split by land and are one huge body of water.

Examples of seas

Mediterranean Sea

Caribbean Sea

Black Sea

North Sea

Last Updated on January 8, 2025 by Emma Vanstone