A marginal sea is a part of ocean partially enclosed by land such as islands, archipelagos, or peninsulas. Unlike mediterranean seas, marginal seas have ocean currents caused by winds like oceans.

Marginal seas of the Pacific Ocean:

• The Bering Sea (separated by the Aleutian Islands)
• The Sea of Japan (by the Japanese Archipelago)
• The Sea of Okhotsk (by the Kurile Islands)
• The South China Sea (by the Philippines)
• The East China Sea (by the Ryukyu Islands)
• The Yellow Sea (by the Korean Peninsula)

Marginal seas of the Atlantic Ocean:

• The North Sea (separated by Great Britain)
• The Irish Sea (by Ireland)

A marginal sea of the Indian Ocean:

• The Andaman Sea (separated by the Andaman and Nicobar Islands)

Seas barely marginal include the Tasman Sea. Seas not marginal include the Arabian Sea.

See sea for the seas of the world.