Area code 925 is a California telephone area code that was split from area code 510 on March 14, 1998. It covers the inland portions of the East Bay counties of Alameda and Contra Costa in the northern area of California.
The area was originally part of area code 415, one of the first three area codes created in California in 1947, which originally covered all of central California. In 1991, area code 510 was created to encompass most of the East Bay. Area code 925 was created March 14, 1998, when area code 510 was split along the natural border of the Berkeley Hills.
The area code includes southeastern Alameda County (Dublin, Pleasanton, Livermore, Sunol, and unincorporated areas surrounding those communities), and all of Contra Costa County except the western part (El Cerrito to Crockett).
Area code 925 has telephone numbers assigned for the central office code 988. 988 has been designated nationwide as a dialing code for the National Suicide Prevention Lifeline, which creates a conflict for exchanges that permit seven-digit dialing. This area code is therefore scheduled to transition to ten-digit dialing, mandatory after October 24, 2021.
Cities in the 925 area code
Contra Costa County
- Alamo Oaks
- Bay Point
- Bethel Island
- Blackhawk-Camino Tassajara
- Discovery Bay
- Marsh Creek Springs
- Norris Canyon
- Pleasant Hill
- San Ramon
- Shore Acres
- Vine Hill
- Walnut Creek
- NANPA area code map of California
- Report on the 925 area code produced by the California Public Utilities Commission, Telecommunications Division
- List of exchanges from AreaCodeDownload.com, 925 Area Code
|North: 707, 916|
|West: 510/341||area code 925||East: 209|
- "Transition to 10-digit dialing (for 988 as 3-digit access to National Suicide Prevention Hotline)" (PDF). North American Numbering Plan Administrator. January 8, 2021. Retrieved March 9, 2021.