The man, 20, was bitten on the legs at around 2pm on Saturday off the coast of Queensland.
A doctor and nurse arrived at the Indian Head on the eastern side of Fraser Island and provided first aid until paramedics were winched down by helicopter.
Despite emergency treatment, the victim could not be saved and died at the scene, the Queensland Ambulance Service said.
The attack happened not far from where 23-year-old Queensland wildlife ranger Zachary Robba was fatally mauled by a great white shark in April.
Fraser Coast Mayor George Seymour told the Australian Broadcasting Corporation that the attack was a tragic event for the community.
He said: “Our deepest condolences go to this young man’s family and friends. The loss of a young life with his future before him is a tragedy beyond words. We share their sadness and grief.”
At least four people have died in shark attacks in Australia this year.
A 57-year-old diver was killed off Western Australia in January and a 60-year-old surfer died near Kingscliff in New South Wales in June.