The incident at Juliana's Fine Jewelry at 1632 Redwood Highway happened around 10:50 a.m., Sgt. Paul Barrolaza said.
A man who was armed with a semi-automatic handgun ordered the store employees to the ground while a second suspect used a tire iron to break the glass tops of several display cases, Barrolaza said.
The third suspect emptied the watches from the display cases into a duffle bag, Barroloza said.
One of the store owners suffered moderate injuries when he was thrown into a display case during a physical altercation with the armed suspect, Barroloza said.
The getaway vehicle, a black Dodge Charger with blue and white paper plates, was seen heading north on Redwood Highway.
The suspects are black males between 6 feet and 6 feet 2 inches and 180 to 210 pounds, police said.
The armed suspect was wearing white high-top basketball shoes and white batting gloves and was carrying a duffle bag, police said.
The suspect with the tire iron was wearing black Easton batting gloves, and the third suspect was wearing black gloves and a black mask. He also was carrying a duffle bag, police said.