| District of California area codes: 510 | |
|---|---|
| Country | United States |
| State/Province | California |
| Major City | San Jose |
| Time Zone | Pacific (UTC-08:00) |
| Prefix | County | Primary City | Company |
|---|---|---|---|
| 510-200 | Alameda | Hayward, CA | Metro PCS |
| 510-201 | Alameda | Oakland, CA | Peerless Network Of California |
| 510-202 | Alameda | Oakland, CA | American Messaging (am) |
| 510-204 | Alameda | Berkeley, CA | Pacific Bell |
| 510-205 | San Francisco | San Francisco, CA | Sprint Spectrum L.p. |
| 510-206 | Alameda | Oakland, CA | New Cingular Wireless PCS |
| 510-207 | Alameda | Oakland, CA | New Cingular Wireless PCS |
| 510-208 | Alameda | Oakland, CA | Pacific Bell |
| 510-209 | Alameda | Hayward, CA | Sprint Spectrum L.p. |
| 510-210 | San Francisco | San Francisco, CA | Bandwidth.com Clec |
| 510-212 | Alameda | Fremont, CA | Usa Mobility Wireless |
| 510-213 | Alameda | Oakland, CA | T-mobile Usa |
| 510-214 | San Francisco | San Francisco, CA | Mci Worldcom Communications, Ca |
| 510-215 | Contra Costa | Richmond, CA | Pacific Bell |
| 510-216 | Alameda | Fremont, CA | Usa Mobility Wireless |
| 510-217 | San Francisco | San Francisco, CA | Teleport Communications Group - San Francisco |
| 510-218 | Alameda | Fremont, CA | Usa Mobility Wireless |
| 510-219 | Alameda | Oakland, CA | New Cingular Wireless PCS |
| 510-220 | Alameda | Oakland, CA | New Cingular Wireless PCS |
| 510-221 | Alameda | Oakland, CA | Sprint Spectrum L.p. |
There are 689 prefixes, In the code area, the major cities are Alameda, CA;Berkeley, CA;Castro Valley, CA;El Cerr. The major city is San Jose.