Family has identified the victims as 60-year-old Valerie Cintora, 60-year-old Shawn Arcadia and Julia Renee Ordunez.
It happened on Overland Avenue and H Street at about 3 pm on Thursday.
The California Highway Patrol says the driver missed a curve and ended up submerged upside down in a canal.
Despite the efforts of good samaritans, two of the victims died at the scene and the third died at the hospital.
Overland Avenue and H Street were closed for several hours as CHP investigated.