| District of California area codes: 925 | |
|---|---|
| Country | United States |
| State/Province | California |
| Major City | Oakland |
| Time Zone | Pacific |
| Prefix | County | Primary City | Company |
|---|---|---|---|
| 925-498 | Contra Costa | San Ramon, CA | U.s. Telepacific Corp. |
| 925-500 | Contra Costa | Martinez, CA | O1 Communications |
| 925-509 | Contra Costa | San Ramon, CA | Usa Mobility Wireless |
| 925-513 | Contra Costa | Brentwood, CA | Pacific Bell |
| 925-516 | Contra Costa | Brentwood, CA | Pacific Bell |
| 925-517 | Contra Costa | Pittsburg, CA | O1 Communications |
| 925-518 | Alameda | Livermore, CA | Sprint Spectrum L.p. |
| 925-519 | Alameda | Pleasanton, CA | Cellco Partnership DBA Verizon Wireless |
| 925-520 | Alameda | Pleasanton, CA | Pacific Bell |
| 925-521 | Contra Costa | Concord, CA | Pacific Bell |
| 925-522 | Contra Costa | Antioch, CA | Pacific Bell |
| 925-523 | Alameda | Pleasanton, CA | Pacific Bell |
| 925-524 | Contra Costa | Clayton, CA | Pacific Bell |
| 925-525 | Alameda | Livermore, CA | Sprint Spectrum L.p. |
| 925-526 | Contra Costa | Pittsburg, CA | U.s. Telepacific Corp. |
| 925-527 | Contra Costa | Walnut Creek, CA | The Telephone Connection Local Services |
| 925-528 | Contra Costa | Orinda, CA | Sprint Spectrum L.p. |
| 925-529 | Contra Costa | Antioch, CA | Cf Communications DBA Telekenex |
| 925-535 | Alameda | Pleasanton, CA | Sprint Spectrum L.p. |
| 925-543 | Contra Costa | San Ramon, CA | Pacific Bell |
There are 552 prefixes, In the code area, the major cities are Antioch, CA;Bay Point, CA;Brentwood, CA;Concord, C. The major city is Oakland.