The body is that of a Caucasian female believed to be between 12 and 16 years old. She was 5 feet 4 inches tall and weighed about 108 pounds. She had brown or black hair, Deputy Coroner Roger Fielding said.
She had no obvious marks or tattoos but she had full braces on her teeth, with red or pink rubber bands, according to the deputy.
She was found wearing tan or faded Hurley brand jeans, a red cotton T-shirt, a black or brown cloth belt and black boots.
On her wrist she was wearing a red and silver Timex watch with a black band, according to Fielding.
The body was found by a couple walking along the beach about a half-mile south of the San Gregorio State Beach entrance around 12:30 p.m. Sunday, San Mateo County sheriff's spokeswoman Rebecca Rosenblatt said.
Coroner Robert Foucrault said his office is in contact with law enforcement agencies in the Bay Area and elsewhere to see if the girl can be matched up to any missing-persons cases.
"It's a case that's getting a lot of our attention," he said.