The tragedy happened on Sunday as the two British tourists were swimming at a beach with no lifeguards, according to a report by the BBC.
A teenage boy, 17, and a man, 46, were swept out to sea near Seventeen Seventy in Queensland.
The pair were declared dead at the scene after being pulled from the water by a police rescue helicopter.
An Australian man is also in a life-threatening condition after being swept out to sea and was airlifted to hospital with serious head injuries.
Police say the injured Australian man was from Monto, a town about 150km inland from Seventeen Seventy.
“We’re not sure whether the third person jumped into the water trying to perform a rescue,” Surf Life Saving Queensland’s Darren Everard told the ABC.
Police are treating the drownings as non-suspicious and will prepare a report for the coroner.
