The two-car crash happened at about 10:20 p.m. on Lake Merced Boulevard near John Muir Drive, south of Lake Merced at the San Mateo County border.
A white four-door Toyota collided head-on with a gray two-door Honda, killing both occupants of the Honda, police said.
The medical examiner’s office identified the men today as Nick Sarmiento, of Daly City, and Robby Macam, of Hercules.
The three occupants of the Toyota were hospitalized with critical injuries. As of Sunday morning, their conditions had stabilized were improving, police said.
Police believe one of the vehicles crossed over into oncoming traffic, but it’s not yet known why. No arrests were made.
“It’s yet to be determined what the cause of the accident was,” police spokesman Officer Albie Esparza said.
He said there was no immediate indication that alcohol or drugs played a role in the crash.