My lil brother does boxing on and off, told me that there is a recently opened up a gym in the East Bay.. The kennel out in San Leandro.
He used to train in Brisbane at a gym called Fire in the Ring.
The local gym I go to, Physique Magnifique in South San Francisco, offers boxing classes (among a lot of other classes,) but imy brother said it's more focused on intro level stuff. He be going there from time to time tho. All the weights on the first floor, they got a ring and boxing equipment down stairs.