The crash occurred on the San Onofre State Beach about 7:35 p.m., authorities reported.
Witnesses said the McDonnell Douglas helicopter was flying south along the coast when they heard a loud bang, and saw sparks flying from the rear of the aircraft. The helicopter then caught on fire, and crashed on the surf.
All three people aboard escaped from the wreckage, and were taken to hospitals for treatment of minor injuries, according to authorities.
The power plant was not impacted by the crash, according to broadcast reports.
The cause of the accident was under investigation.