According to authorities, the four-door car was traveling southbound on Navy Way north of Pier 300 and crashed just before 3 p.m.
"We have witnesses who observed the driver on the wrong side of the roadway," said Los Angeles Police Sergeant Sgt. Jerome Calhoun. "All of a sudden he veered to his right to switch back over to the right side of traffic, which caused him to run off the road. His vehicle then plunged into the ravine."
The car landed in water about 8 feet deep.
Divers broke a window and pulled the driver out. He was taken to a nearby hospital in grave condition. He later died of his injuries.
There were no other passengers in the car.
It's not clear what caused the accident.
The wreckage was removed from the water about 5 p.m. Police said they planned to inspect the car to see if it had mechanical problems.