You know the five oceans from The Five Oceans: the Pacific, Atlantic, Indian, Southern and Arctic, from largest to smallest. Around their edges are smaller bodies of salt water called seas, gulfs and bays.
Key idea
A sea is a smaller part of the ocean, partly enclosed by land. The Mediterranean, Caribbean, Arabian, South China, North, Black, Red and Bering Seas are some of the most important.
| Sea | Part of which ocean | Land around it |
|---|---|---|
| Mediterranean Sea | Atlantic | Southern Europe, North Africa, Southwest Asia |
| Caribbean Sea | Atlantic | Central America, the Caribbean islands, northern South America |
| North Sea | Atlantic | Great Britain, Norway, Denmark, Germany, the Netherlands |
| Arabian Sea | Indian | Arabian Peninsula, Pakistan, India |
| Red Sea | Indian | Northeast Africa and the Arabian Peninsula |
| South China Sea | Pacific | China, Vietnam, the Philippines, Malaysia |
| Bering Sea | Pacific | Russia and Alaska |
| Black Sea | Atlantic, through the Mediterranean | Türkiye, Ukraine, Russia, Georgia, Bulgaria, Romania |
Why it works
All the oceans are joined into one World Ocean; the names are a way to talk about its parts. A sea is named where land closes in around part of the ocean, so its water, waves and life can differ from the open ocean. The Black Sea connects to the Mediterranean through narrow straits, and the Mediterranean to the Atlantic through the Strait of Gibraltar.
Worked example: Which ocean?
A ship sails from the Red Sea into open water to the south. Which ocean is it in?
- The Red Sea opens at its south end into the Gulf of Aden and the Arabian Sea.
- Those are parts of the Indian Ocean.
Answer: The Indian Ocean.
Common mistake
Thinking a sea is the same as a lake, or that every "sea" is part of the ocean. Most seas are arms of the ocean. But the Caspian Sea and the Dead Sea are salty lakes: land surrounds them, and their water never reaches the ocean. Check the map: does the water connect to an ocean?