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Spam calls from area code 831? Here’s how to stop them.

Area code 831 covers Monterey, CA — but the spammers calling you aren’t there. They’re faking it. Here’s the fix.

If your phone keeps lighting up with calls from area code 831, here’s the truth: it’s almost certainly not someone in Monterey, CA. It’s a robocaller spoofing a the Central Coast number so the call looks local and you pick up. You hang up, they dial the next 831 number. You are one row in a spreadsheet.

The move isn’t to block 831. Real calls come from 831 too. The move is to screen it — known callers ring through, unknown 831 numbers hit a wall first.

Why 831 specifically?

Spoofing engines pull the first six digits of your number and dial out matching 831 numbers — the “neighbor” trick. A call that shares your area code and prefix feels safe, so answer rates jump. That’s the entire scam: familiarity. Learn the mechanics in neighbor spoofing and why you got picked in why me?

Shut down 831 spam calls — free

  1. Silence unknown callers. The single biggest win. Set it up on iPhone or Android in 30 seconds.
  2. Turn on your carrier’s filter. Free on AT&T, Verizon, and T-Mobile.
  3. Register on the Do Not Call list. Won’t stop scammers, but it makes the legal ones back off and gives you standing to report.
  4. Weaponize the rest. The calls that still get through? Hand them to the Crew — an AI answers in character and wastes the scammer’s time on a call they thought was a live mark.

Why am I getting spam calls from area code 831?

Because scammers spoof it. Auto-dialers fake a 831 (Monterey) number so the call looks local and you’re more likely to answer. The caller is almost never actually in Monterey — the number is a mask. This is called neighbor spoofing.

Is a call from 831 always spam?

No. Real people and businesses in Monterey use 831 too. That’s exactly why blanket-blocking the whole area code backfires — you’d miss real calls. The fix is screening: let known contacts ring through and send unknown 831 numbers to a screener first.

How do I stop 831 spam calls for free?

Turn on Silence Unknown Callers (iPhone / Android), register on the Do Not Call list, and add your carrier’s free spam filter. For the ones that still slip through, hand them to the Crew and let AI waste their time instead of yours.

More in this guide

Spam calls from area code 858? Here’s how to stop them.Getting spam calls from 858? It’s neighbor spoofing — not really San Diego, CA. Here’s why, and how to block 858 spam calls free on iPhone & Android.Read the guide →Spam calls from area code 909? Here’s how to stop them.Getting spam calls from 909? It’s neighbor spoofing — not really San Bernardino, CA. Here’s why, and how to block 909 spam calls free on iPhone & Android.Read the guide →Spam calls from area code 916? Here’s how to stop them.Getting spam calls from 916? It’s neighbor spoofing — not really Sacramento, CA. Here’s why, and how to block 916 spam calls free on iPhone & Android.Read the guide →Spam calls from area code 925? Here’s how to stop them.Getting spam calls from 925? It’s neighbor spoofing — not really Concord, CA. Here’s why, and how to block 925 spam calls free on iPhone & Android.Read the guide →Spam calls from area code 949? Here’s how to stop them.Getting spam calls from 949? It’s neighbor spoofing — not really Irvine, CA. Here’s why, and how to block 949 spam calls free on iPhone & Android.Read the guide →Spam calls from area code 951? Here’s how to stop them.Getting spam calls from 951? It’s neighbor spoofing — not really Riverside, CA. Here’s why, and how to block 951 spam calls free on iPhone & Android.Read the guide →Spam calls from area code 760? Here’s how to stop them.Getting spam calls from 760? It’s neighbor spoofing — not really Palm Springs, CA. Here’s why, and how to block 760 spam calls free on iPhone & Android.Read the guide →Spam calls from area code 805? Here’s how to stop them.Getting spam calls from 805? It’s neighbor spoofing — not really Santa Barbara, CA. Here’s why, and how to block 805 spam calls free on iPhone & Android.Read the guide →Spam calls by area codeThe full pillar — every guide in this series.Read the guide →
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