| District of California area codes: 925 | |
|---|---|
| Country | United States |
| State/Province | California |
| Major City | Oakland |
| Time Zone | Pacific |
| Prefix | County | Primary City | Company |
|---|---|---|---|
| 925-326 | Contra Costa | Concord, CA | Level 3 Communications |
| 925-327 | Contra Costa | San Ramon, CA | Pacific Bell |
| 925-328 | Contra Costa | San Ramon, CA | Pacific Bell |
| 925-330 | Contra Costa | Walnut Creek, CA | New Cingular Wireless PCS |
| 925-331 | Contra Costa | Antioch, CA | U.s. Telepacific Corp. |
| 925-332 | Contra Costa | Concord, CA | Peerless Network Of California |
| 925-333 | Contra Costa | Walnut Creek, CA | American Messaging (am) |
| 925-334 | Contra Costa | Concord, CA | Cellco Partnership DBA Verizon Wireless |
| 925-335 | Contra Costa | Martinez, CA | Pacific Bell |
| 925-336 | Contra Costa | San Ramon, CA | New Cingular Wireless PCS |
| 925-337 | Alameda | Livermore, CA | Cellco Partnership DBA Verizon Wireless |
| 925-338 | Contra Costa | Concord, CA | Bandwidth.com Clec |
| 925-339 | Alameda | Livermore, CA | Metro PCS |
| 925-340 | Contra Costa | Walnut Creek, CA | Usa Mobility Wireless |
| 925-341 | Contra Costa | Antioch, CA | American Messaging (am) |
| 925-342 | Contra Costa | Antioch, CA | American Messaging (am) |
| 925-343 | Alameda | Pleasanton, CA | American Messaging Services |
| 925-344 | Alameda | Livermore, CA | Mpower Communications Corp |
| 925-345 | Contra Costa | Danville, CA | American Messaging (am) |
| 925-346 | Contra Costa | Concord, CA | American Messaging (am) |
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.