It happened at a popular beach in New South Wales yesterday.
Police say a couple and their three children were in shallow water at Lennox Head, when their daughter was swept out to sea on a body board.
Her father swam out to her but wasn't able to bring her back to shore.
His wife and the girl were able to reach the beach and raise the alarm.
The Department of Foreign Affairs says it is aware of this case, and is providing consular assistance.
