831 Area Code — California
831 is a North American Numbering Plan area code for California, the United States. It covers about 757,058 people in 37 towns and 57 ZIP codes, including Salinas, Santa Cruz and Watsonville.
| Field | Value |
|---|---|
| Area code | 831 |
| Country | United States (+1) |
| State / province | California |
| Type | Standalone (no other NANP code covers the same towns) |
| Time zone | Pacific |
| Population covered | 757,058 |
| Towns covered | 37 |
| ZIP codes | 57 |
| Approx. centre | 36.733, -121.738 |
Where area code 831 is used
Area code 831 is assigned to California, the United States, inside the North American Numbering Plan. Numbers in the code are written (831) NXX-XXXX at home and +1 831 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 831
The 37 towns below are the largest in the 831 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 |
|---|---|---|---|
| Salinas | Monterey County | 195,417 | 8 |
| Santa Cruz | Santa Cruz County | 100,040 | 6 |
| Watsonville | Santa Cruz County | 82,806 | 2 |
| Hollister | San Benito County | 59,889 | 2 |
| Monterey | Monterey County | 33,280 | 4 |
| Seaside | Monterey County | 32,266 | 1 |
| Marina | Monterey County | 28,122 | 1 |
| Soledad | Monterey County | 27,471 | 1 |
| Aptos | Santa Cruz County | 24,951 | 2 |
| Greenfield | Monterey County | 21,574 | 1 |
| King City | Monterey County | 17,243 | 1 |
| Scotts Valley | Santa Cruz County | 15,135 | 2 |
Counties covered
| County | ZIP codes |
|---|---|
| Monterey County | 32 |
| Santa Cruz County | 21 |
| San Benito County | 4 |
Nearby area codes
How to dial area code 831
- Within North America: 831 + 7-digit number (831-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 831, then the 7-digit number — for example 00 1 831 NXX-XXXX from most of Europe.
Frequently asked questions
What area code is 831?
831 is a North American Numbering Plan area code assigned to California, the United States. It covers about 757,058 people in 37 towns.
Is 831 a US or Canadian area code?
831 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 831 in?
Area code 831 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.