The male passenger was seen falling from the ship, the Rhapsody of the Seas, at about 2 a.m. Saturday morning, the Australian Broadcasting Corp. reported.
The ship was 340 miles east of Brsibane on a trip from Sydney to New Caledonia at the time.
The ship stopped and turned around immediately, Royal Caribbean International said in a statement.
The Australian Maritime Safety Authority, a Queensland Government plane, another cruise ship and a merchant ship were called to assist with the search.
Rhapsody of the Seas crew spotted the man's body at about 8 a.m. and pulled him from the water.
Investigations are under way and a coroner will prepare a report, the ABC reported.