His yellow 1946 Aeronca plane crashed into the water about 10 miles off the coast at about 3 p.m.
A Coast Guard C-130 airplane on a training mission nearby responded to the crash and dropped a life raft, survival suit and flares to the pilot and sole occupant of the plane, according to the Coast Guard. Two Coast Guard boats also went to the area.
"We were just in the right place at the right time," said Coast Guard Lt. Randall Black, the pilot of the C-130.
An Air National Guard helicopter, which had just completed joint training operations with the Coast Guard and was headed to Air Station San Francisco, also responded to the area and liftedthe man out of the water at about 3:20 p.m.
Black said the pilot suffered "extreme hypothermia" and was taken to San Francisco General Hospital.
The victim's plane sunk and is unsalvageable, according to the Coast Guard.