It happened just before 10 p.m. near PCH and Sunset Boulevard, just north of Pacific Palisades.
According to the Los Angeles Police Department, the people who were inside the car that went into the water fled the scene. Officers spotted them along the beach shortly after and placed them into custody.
It's unclear what caused the crash and there's no word of any injuries.
The southbound lanes of PCH in the area are currently shut down due to the investigation.
Footage from AIR7 HD showed a mangled car on the highway and another sitting on the rocks in the surfline.
Drivers in the area are urged to seek an alternate route.