Sea is a smaller body of saltwater that is partly enclosed by land or connected to an ocean. Seas are usually shallower than oceans and may be surrounded by coastlines. They can have waves, currents, and tides. Some seas are almost completely enclosed by land.

Seas are found along the edges of oceans or surrounded by land, such as the Mediterranean Sea and the Baltic Sea. They exist as part of Earth’s water system over long periods. Seas support many types of marine life. People use seas for fishing, travel, and trade.