The robberies occurred at about 12:25 p.m. on Oct. 29 at a Bank of the West at 701 Santa Cruz Ave. and at about 2 p.m. on Nov. 8 at a U.S. Bank at 1105 El Camino Real, according to the FBI.
In each robbery, the suspect gave a bank teller a note demanding money and said she had a gun.
During the October robbery, she wore a red Cincinnati Reds baseball cap with a "C" on it, along with sunglasses, a dark gray hooded jacket and gray sweatpants, FBI officials said. She was carrying a dark bag.
In the November robbery, she wore a light blue and gold Denver Nuggets hat with the word "Nuggets" and a graphic on it, along with a long-sleeve green sweatshirt and blue jeans, according to the FBI. That day, she was carrying a light brown handbag.
The FBI released surveillance images of the suspect, who is described as a Pacific Islander or Hispanic woman between 25 and 30 years old. She is about 5 feet 7 or 5 feet 8 inches tall, weighs between 140 and 170 pounds and has brown eyes and brown hair.
The suspect should be considered armed and dangerous. Anyone with information on her whereabouts is asked to call 911 or the FBI's San Francisco office at (415) 553-7400. Tips can also be submitted online at tips.fbi.gov.