A spokesman with the San Francisco Fire Department says the boy was revived and is expected to make a full recovery.
San Francisco Police Officer Giselle Talkoff says the boat carrying 27 adults and three children capsized for unknown reasons Saturday afternoon about 100 yards off Pier 45.
Talkoff says five adults and two other children were also taken to hospitals. One was another 5-year-old boy who was initially listed in critical condition but is now stable.
A fire department official says all are expected to survive.