925 Area Code — California
925 is a North American Numbering Plan area code for California, the United States. It covers about 1,128,993 people in 23 towns and 40 ZIP codes, including Concord, Antioch and Pittsburg.
| Field | Value |
|---|---|
| Area code | 925 |
| Country | United States (+1) |
| State / province | California |
| Type | Standalone (no other NANP code covers the same towns) |
| Time zone | Pacific |
| Population covered | 1,128,993 |
| Towns covered | 23 |
| ZIP codes | 40 |
| Approx. centre | 37.872, -121.930 |
Where area code 925 is used
Area code 925 is assigned to California, the United States, inside the North American Numbering Plan. Numbers in the code are written (925) NXX-XXXX at home and +1 925 NXX-XXXX when dialled from outside Canada and the United States. Since the NANP moved to 10-digit dialling you must always include the area code, even for a local call.
Towns and cities in area code 925
The 23 towns below are the largest in the 925 footprint, ranked by population. Every one of them links to its own page with the full list of area codes and ZIP codes for that town.
| Town | County | Population | ZIP codes |
|---|---|---|---|
| Concord | Contra Costa County | 125,693 | 8 |
| Antioch | Contra Costa County | 116,477 | 2 |
| Pittsburg | Contra Costa County | 100,488 | 1 |
| Walnut Creek | Contra Costa County | 90,740 | 4 |
| Livermore | Alameda County | 87,758 | 2 |
| San Ramon | Contra Costa County | 87,007 | 2 |
| Pleasanton | Alameda County | 78,550 | 2 |
| Dublin | Alameda County | 70,803 | 1 |
| Brentwood | Contra Costa County | 69,755 | 1 |
| Danville | Contra Costa County | 59,639 | 2 |
| Martinez | Contra Costa County | 48,643 | 1 |
| Oakley | Contra Costa County | 46,368 | 1 |
Counties covered
| County | ZIP codes |
|---|---|
| Contra Costa County | 34 |
| Alameda County | 6 |
Nearby area codes
How to dial area code 925
- Within North America: 925 + 7-digit number (925-NXX-XXXX). The leading 1 is optional on a mobile phone and required on most landlines for long-distance.
- From abroad: your country's international prefix, then 1, then 925, then the 7-digit number — for example 00 1 925 NXX-XXXX from most of Europe.
Frequently asked questions
What area code is 925?
925 is a North American Numbering Plan area code assigned to California, the United States. It covers about 1,128,993 people in 23 towns.
Is 925 a US or Canadian area code?
925 is a United States area code. Canada and the United States share the +1 country code, so both are part of the same numbering plan.
What time zone is area code 925 in?
Area code 925 is in the Pacific time zone.
Do I have to dial 10 digits?
Yes. Every NANP call now requires the area code plus the seven-digit number, even for a local call.