Lifeguards have reopened the Basin at Rottnest Island after several earlier shark sightings.
According to Surf Lifesaving WA a 3.5m unknown species shark was sighted at Parker Point about 500m offshore on Tuesday.
The sighting was reported just after 10.20am.
Earlier the Westpac Helicopter reported seeing two 3m hammerhead sharks west of Rottnest Island.
But by 11.30am Rottnest Island lifeguards at the Basin reopened the beach after no further sightings.