Rangers have closed Rockingham Beach after a 2.5 metre shark was spotted offshore.
The Surf Life Saving helicopter sighted the shark around 9.40am on Monday off the RO24 Rockingham BEN sign on Rockingham Beach Road.
It was swimming about 200 metres offshore and tracking west.
The species of shark is unknown.
The helicopter also sighted two hammerhead sharks around 10.10am at Point Peron beach about 300m offshore.
Nearly 100 new rentals to be built in Mandurah
Blue swimmer crabs off limits during season closure
Fire crews on scene of Meadow Springs house fire
Perth's southern suburbs declared One Nation's 'heartland' after Secret Harbour by-election victory
Construction contract awarded for Kwinana Freeway upgrade
Port Kennedy humpback whale buried at landfill facility
Secret Harbour by-election: Where to vote on August 29
Mandurah man charged over role in alleged sophisticated cybercrime syndicate
Locals urged to look out for man who removed electronic monitoring device