Beach Margaret River Mouth Beach (WA 660) lies across the mouth of the usually blocked river. The beach faces southwest and curves for 500 m between boundary calcarenite bluffs of the old valley side to the south and a low reef to the north, where it forms a sandy foreland. It is backed by the dammed river which can break out and either end of the beach, resulting in a flat overwashed area behind the steep beach.The beach is partly protected by reefs, with waves increasing in height up the beach to about 1 m. Lower waves break right on the steep beach, with higher waves breaking as a heavy shorebreak or heavily on a narrow bar. The short heavy beach break, known as Margaret River Mouth, while a hazard to swimmers does attract surfers when waves exceed 1 m.The Margaret River Surf Life Saving Club was provisionally established at this beach in 2003 and patrols the beach on Sundays during the summer period.
Swimming Margaret River beach is (WA 660) the more popular swimming beach and is relatively safe under normal conditions. However watch the rip against the southern rocks, and the shorebreak when waves exceed 1 m Gnarabup Beach (WA 658) usually has low waves lapping against the steep beach.
Surfing Margaret River produces one of the world’s great lefts on the inner and outer reef, the outer reef holding waves to several metres high. During average swell conditions there is also a shorter right across the inner reef. The river mouth beach can also produces a dumpy shore break.