Coast Guard officials said in a news release that the unidentified passenger fell from a deck of the Norwegian Pearl about 7 p.m. Thursday.
Officials say a Coast Guard cutter and a C-130 plane were responding to assist in the search.
Norwegian Cruise Line said in an emailed statement that a female passenger was seen intentionally going overboard during a chartered cruise on the Pearl.
The cruise line says crew members immediately initiated rescue measures, including deploying three rescue boats and notifying authorities.
The statement says the ship and charter company teams are providing support to the family and impacted guests.