Police said the suspect entered the Chase Bank at 4520 Dublin Blvd. at about 5:50 p.m. Wednesday and handed the teller a note saying he had a gun and wanted money.
The teller complied with the suspect's orders and the suspect left the bank with an undetermined amount of cash, according to police.
The suspect did not speak to the teller, no gun was seen and no employees or customers were injured during the incident, police said.
Police said the suspect is described as a white man between 20 and 30 years old who is about 5 feet 11 inches to 6 feet 1 inch tall and was wearing a blue sweat jacket, a black baseball cap and blue jeans.
The suspect also had a bushy beard but it was possibly a fake and was similar to the beard sported by Brian Wilson, a former San Francisco Giants pitcher who now plays for the Los Angeles Dodgers, police said.
The bank robbery was the second on Dublin Boulevard in two days.
A suspect robbed the Bank of America branch at 4250 Dublin Blvd. at 11:43 a.m. Tuesday. However, the description of the suspects in the two cases was different, police said.
Dublin police said anyone with information about the bank robbery should call Detective Miguel Campos at (925) 556-4561 or Detective Dan McNaughton at (925) 833-6696.