Here are the 15 “zoos” that I’ve visited that are all within an approximate 1.5-hour radius of the Bay Area:
Aquarium of the Bay (San Francisco)
California Academy of Sciences (San Francisco) - Steinhart Aquarium
California Raptor Center (Davis)
CuriOdyssey (San Mateo)
Folsom City Zoo Sanctuary (Folsom)
Happy Hollow Park & Zoo (San Jose)
Lindsay Wildlife Experience (Walnut Creek)
Marine Mammal Center (Sausalito)
Micke Grove Zoo (Lodi)
Oakland Zoo (Oakland)
Palo Alto Junior Museum & Zoo (Palo Alto)
Safari West Wildlife Preserve (Sonoma County)
San Francisco Zoo (San Francisco)
Six Flags Discovery Kingdom (Vallejo)
Sulphur Creek Nature Center (Hayward)
Almost all of them are reviewed on my
Snowleopard's 2017 Road Trip thread (not Oakland or Happy Hollow), when I toured 44 zoos in California. My recommendation would definitely be to visit
Oakland Zoo, as I've only been once before and that was back in 2011. Since then, the zoo has doubled in size with the addition of the California Trail zone in 2018.
Snowleopard's 2017 Road Trip