The incident involved an MV-22 Osprey tilt-rotor aircraft, the III Marine Expeditionary Force based in Okinawa, Japan said in a statement.
"The aircraft involved in the mishap had launched from the USS Bonhomme Richard (LHD 6) and was conducting regularly scheduled operations when the aircraft entered the water," the statement said.
"The ship's small boats and aircraft immediately responded in the search and rescue efforts."
Australia's defence minister said in a statement that no Australian Defence Force personnel were on board. The incident occurred off the coast of Shoalwater Bay, in the state of Queensland, the statement said.
Michael Augustus, a spokesman for Queensland Ambulance, said one person had been taken to Rockhampton hospital, but he gave no further details of the circumstances and no details of the person's condition.
The defence minister, Marise Payne, said she had briefed the US defense secretary and the Australian prime minister.
The US Marine Corps said the incident was under investigation but gave no additional information.
More than 33,000 US and Australian military personnel, including the Bonhomme Richard Expeditionary Strike Group, participated in the recent Talisman Saber joint military exercise in Australia which ended on July 25, according to a statement from the US Army Public Affairs Office.
The exercise included participation from MV-22 Osprey practicing the deployment of US Marine Corps reconnaissance teams.
Australia is a military ally of the United States.
(Reporting by Tom Westbrook and Colin Packham in SYDNEY and Jamie Freed in SINGAPORE; Editing by Gareth Jones and Dale Hudson)
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)