What is the only sea without coasts?

The Sargasso Sea is the only named sea without land boundaries. Instead of being enclosed by coastlines, it is defined by four major ocean currents in the North Atlantic.

The Gulf Stream forms its western boundary, the North Atlantic Current lies to the north, the Canary Current marks the east, and the North Atlantic Equatorial Current borders the south. Together, these currents create part of the clockwise North Atlantic Gyre and continually shape the sea’s location.

The Sargasso Sea is named for Sargassum, a brown seaweed that floats in large rafts at the surface. The sea’s calm, clear blue water and floating vegetation provide important habitat for young eels, sea turtles, fish, and seabirds. Bermuda lies near its western edge.

A common mix-up is treating “sea” as a strict synonym for a coastal body of water. Seas are often partly enclosed by land, but the Sargasso Sea is a named ocean region identified by currents. Other options, including the Mediterranean, Caribbean, and Baltic seas, all have recognizable land boundaries.