The 831 area code serves California’s Central Coast and the Monterey Bay region. Created in 1998 in a split from area code 408, it stretches from the surf town of Santa Cruz through the agricultural Salinas Valley to the historic Monterey Peninsula. If an 831 number has appeared on your caller ID, this guide explains where it comes from, how to dial it, and how to stay safe from spoofed calls.
Quick Summary: Area Code 831 at a Glance
| Detail | Information |
|---|---|
| Area Code | 831 |
| State | California (CA) |
| Major Cities | Salinas, Santa Cruz, Monterey, Watsonville |
| Time Zone | Pacific Time (PT) |
| Country Code | +1 (USA) |
| Overlay Codes | None (standalone) |
Geographic Coverage & Major Cities
Area code 831 covers California’s Central Coast, spanning Monterey, Santa Cruz, and San Benito counties around the shores of Monterey Bay. It reaches from the northern Santa Cruz coastline, down through the fertile Salinas Valley, and out along the Monterey Peninsula.
Cities and communities served by the 831 area code include:
- Salinas – the largest city and seat of Monterey County, and hometown of author John Steinbeck
- Santa Cruz – famous for its beach boardwalk and the University of California, Santa Cruz
- Monterey, Pacific Grove & Carmel-by-the-Sea – the scenic, tourism-driven Monterey Peninsula
- Watsonville & Hollister – agricultural hubs inland from the bay
From world-class tourism at Pebble Beach and Big Sur to one of the most productive farming regions in the country, an 831 number is closely tied to the relaxed coastal identity of the Monterey Bay area.
A Brief History of Area Code 831
Area code 831 was created on July 11, 1998, in a geographic split from area code 408. As Silicon Valley boomed, 408 ran short of available numbers, so the Central Coast counties of Monterey, Santa Cruz, and San Benito were carved out into the new 831 code while 408 retained San Jose and the southern Bay Area. Unlike many California regions, 831 has never needed an overlay and continues to serve the entire Central Coast on its own.
Time Zone & Best Time to Call
Numbers in the 831 area code use Pacific Time (PT). The region observes Daylight Saving Time, shifting from PST (UTC-8) to PDT (UTC-7) between March and November each year.
How to Dial Phone Numbers in Area Code 831
Because 831 has no overlay, both 7-digit and 10-digit local dialing have historically worked, but 10-digit dialing is now the recommended standard across the United States.
Calling within the United States or Canada
- 10-digit dialing: Include the area code – 831-XXX-XXXX.
- 11-digit dialing: You can also dial 1-831-XXX-XXXX; the leading 1 is the NANP country code.
Calling from outside the United States
- Format: [exit code] + 1 + 831 + XXX + XXXX
- From the UK, Europe, or most of Asia/Africa: 00 1 831 XXX XXXX
- From any mobile phone worldwide: +1 831 XXX XXXX
Is Area Code 831 a Scam? Safety & Protection Tips
Area code 831 is a legitimate California area code – a call from it is not fraudulent by default. However, scammers frequently spoof local codes like 831, faking the caller ID so their number appears to come from a trusted Central Coast line. Neighbor spoofing, which mimics the first six digits of your own number, is especially common.
Common scam tactics linked to this region
| Scam type | What to watch for |
|---|---|
| Government impersonation | Callers posing as the IRS or SSA threatening arrest or fines |
| Bank & card fraud alerts | Claims of “suspicious activity” seeking your account details |
| Utility shut-off threats | Demands for immediate payment to avoid disconnection |
| Package delivery scams | Fake texts or calls about a “failed delivery” with a bad link |
How to report, block, and look up 831 callers
- Never share personal or financial details with an unexpected caller, however urgent they sound.
- Block the number using your phone’s built-in call-blocking feature or a reputable call-screening app.
- Look up the number with a trusted reverse phone lookup before returning any call.
- Report it to the FTC at reportfraud.ftc.gov and register at DoNotCall.gov.
Nearby & Related Area Codes in California
Area code 831 borders several other California codes:
- 408 & 669 – San Jose and the southern Bay Area (see our 408 area code guide)
- 650 – the San Francisco Peninsula (see our 650 area code guide)
- 559 – Fresno and the central San Joaquin Valley (see our 559 area code guide)
- 805 – San Luis Obispo and Santa Barbara to the south (see our 805 area code guide)
Explore more codes across the state on our California area codes hub, or browse every prefix in our US area codes directory.
↑ See the complete list of All US Area Codes by State – every area code across all 50 states in one directory.
Explore Neighboring States
Researching area codes just across the state line? Start with these codes in the states that border California:
Frequently Asked Questions About Area Code 831
Where is the 831 area code located?
Area code 831 covers California’s Central Coast, including Santa Cruz, Salinas, Monterey, and Watsonville. It operates on Pacific Time and serves the counties around Monterey Bay.
Is 831 a landline or cell phone area code?
Both. Area code 831 serves landlines, mobile phones, and VoIP numbers throughout the Central Coast.
Does the 831 area code have an overlay?
No. Unlike most California metro codes, 831 has no overlay, so it still covers its entire region on a single area code with no second code layered on top.
Should I answer a call from an unknown 831 number?
If you are not expecting the call, let it go to voicemail. Legitimate callers leave a message, while spoofed or robocall numbers usually will not. Verify any unfamiliar number with a reverse lookup before calling back.
Related 831 Guides
- Is a 831 call safe? Read Is area code 831 a scam? Spam & safety guide.
- Worried about spam or robocalls? Browse our Scam Alerts directory.