How do waves make sea foam?

A breaking wave mixes air into seawater. Some air becomes trapped in little bubbles near the surface. Groups of these bubbles can gather into sea foam.

Seawater contains substances from living things, including tiny sea organisms. Some of these substances help the thin watery walls around bubbles last longer. The bubbles do not all pop immediately.

Wind and more waves can gather the bubbles into frothy patches along the shore. A patch can grow and then disappear as bubbles break. Sea foam is mostly air held in watery films, rather than a new solid washed out of the sea.