The U.S. Marine Corps identified the victims as Corporal Jason Chleborad, 22, of Rapid City, S.D., Corporal Christopher Arzola, 21, of Westfield, Mass., and Sgt. Jeremiah Callahan, 23, of Chadron, Neb.
A fourth Marine, who has not been identified, remains in serious condition.
The Marines were driving through Dana Point around 2 a.m. on Tuesday when their car slammed into a palm tree on Golden Lantern and Terra Vista. Authorities said the driver, who is the sole survivor of the crash, was driving too fast and lost control.
The victims were all active-duty Marines stationed at Camp Pendleton.
The accident is under investigation.