Aldinga Beach great white shark spotted coasting shoreline south of Adelaide

A “boat-sized” great white shark was seen swimming dangerously close to a popular beach, prompting a public alert.

The four-metre measured predator was lurking off the coast of Aldinga Beach, south of Adelaide, at 8:30am on Saturday.

Fishermen in a boat filmed the moment when it came within 500 m of the beach and precariously close to their boat.

The shark swam just below the surface of the water with a size comparable to the ship that sailed alongside it.

The animal was seen before the surf rescue team was on duty and the police were called to help raise the alarm for bathers.

Photos of the giant predator were uploaded to Facebook as a warning and viewers shared their disbelief at its size.

“Don’t think I’ll be swimming too far next week,” one person wrote.

A second added: “I’m fine if I stay in the shallows.”

Great white sharks can reach up to six meters in length and weigh up to 3,000 kg.

They are found predominantly along the coast from Moreton Bay in Queensland, along the southern coast of Australia, and near the West Cape in Western Australia.

Their diet includes squid, fish, seals, sea lions, and dolphins.

British diving instructor Simon Nellist was attacked from below in February 2022 by a 13ft long predator at Buchan Point near Little Bay in Sydney.

It was the first fatal shark attack in the region in decades after Actress Marcia Hathaway, 32, was mutilated during a boating trip in Sugarloaf Bay, in Middle Harbor, in 1963.