UPDATE: 12:20pm All Perth beaches have reopened after a series of shark sites off the coast of Swanbourne, City Beach and Floreat beaches today.
The latest reported sighting occurred about 11am when a shark was spotted about 200m from shore near Swanbourne Military Range.
Swanbourne and North Cottesloe Beaches were closed as a result.
Just minutes before that, a 2.5m tiger shark was spotted about 650m off Floreat Beach heading south at 12pm.
Floreat and City Beaches, which was already closed due to shark sightings from about 7.30am this morning, remained closed until 11.30am.
At 7.30am a group of tiger sharks were seen feeding on bait fish about 800m from shore.
Surf Life Saving WA Westpac Rescue Helicopter then spotted a second 3.5m tiger shark 350m offshore at City Beach.
Surf Life Saving also tweeted that a shark had been spotted by a surfer at Strickland Bay, Rottnest, about 8.50am.