Coast Guard crews began searching today for a Quantum of the Seas cruise ship passenger who went overboard 500 miles south of Kailua-Kona while the vessel was en route from Brisbane, Australia, to Honolulu after a stopover in Tahiti.

Joint Rescue Coordination Center Honolulu received a report from the ship of a man from Australia going overboard at 11:03 p.m. Tuesday. The crew of Quantum of the Seas, which is operated by Royal Caribbean International, remained on scene to search for about two hours, deploying six life rings, according to the U.S. Coast Guard.

A Coast Guard Air Station Barbers Point C-130 Hercules aircrew launched at 7 a.m. and arrived on scene at about 9 a.m. to begin searching.

After six hours on scene, the crew returned to Air Station Barbers Point for fuel replenishment. The search will resume at first light Thursday morning.

The cruise ship has been at sea for 15 days after departing Brisbane, Australia, on April 12 and is expected to dock in Honolulu on Friday.

“While on its trans-Pacific sailing, a guest onboard Quantum of the Seas went overboard,” Royal Caribbean said in a statement. “The ship’s crew immediately launched a search and rescue operation and is working closely with local authorities.”