This article is about the geographical feature. For other uses of lagoon, see Lagoon (disambiguation).
Balos coastal lagoon of northwestern Crete. The shallow lagoon is separated from the Mediterranean sea by narrow shoals connecting to a small, rocky mountain.
A lagoon is a shallow body of water separated from a larger body of water by barrier islands or reefs. Lagoons are commonly divided into coastal lagoons and atoll lagoons. They have also been identified as occurring on mixed-sand and gravel coastlines. There is an overlap between bodies of water classified as coastal lagoons and bodies of water classified as estuaries. Lagoons are common coastal features around the world.