San Francisco Police Sgt. Wilfred Williams said Sunday that the wounds to the 19-year-old man, 15-year-old girl and 12-year-old girl were not life-threatening.
Williams says they had been at a private party at Sinbad's restaurant late Saturday night when an argument led to several shots being fired inside and outside the restaurant.
Sinbad's is a 35-year-old upscale seafood restaurant on Pier 2 of San Francisco's Embarcadero.
Police say they detained several people after the shootings. One man was arrested on a weapons charge, but it was not immediately clear whether he was involved in the shooting.