Firefighters were dispatched around 7:10 p.m. regarding an approximately 30-foot boat fully engulfed in flames in the 700 block of Queensway Drive between Hotel Maya and the Queen Mary, according to the Long Beach Fire Department.
Video showed black smoke coming from the boat, which was about 100 feet from shore.
There was a total of seven victims; they were spotted floating in a dinghy nearby. Four of them were taken to a hospital in unknown condition.
Firefighters extinguished the blaze around 8:15 p.m., and the boat was later taken to Long Beach Fire Station 21.
It's unclear what caused the fire.
City News Service contributed to this report.