A Mercedes heading southbound collided with a minivan heading north around 8:20 p.m., according to the CHP.
"The collision sadly enough resulted in three fatalities," said CHP Sgt. Nick Salmeron. "Two occupants in the minivan - an elderly husband and wife, it appears, and a sole occupant in the Mercedes."
Two juveniles were also transported by ambulance to a local hospital, one with minor injuries and one with major injuries, he said.
Officials are investigating the cause of the accident.
PCH was expected to be closed in that area for several hours.