The only other person aboard the helicopter was the pilot.
The passenger reportedly opened the door and jumped out into the water near the Balboa Pier.
The 60-year-old Caucasian man was hospitalized in critical condition after lifeguards located and rescued the victim. He was pronounced dead at the local hospital.
The helicopter pilot was instructed to land at John Wayne Airport to be interviewed.
The victim was not identified pending notification of next of kin.
The incident was being investigated as a possible suicide, according to the Newport Beach Police Department.