How to Block Scam Calls on iPhone: 5 Settings That Actually Work

TLDR

Your iPhone has built-in tools to block most scam calls without any third-party apps. The most effective single setting is Silence Unknown Callers, which blocks the majority of robocall scam numbers. Combined with carrier-level filtering and manual blocking, you can eliminate most unwanted calls.

Why This Matters: The Numbers

ScamVerify™ analyzed over 1.5 million FTC complaints and found a pattern that changes how you should think about call blocking:

• Toll-free numbers (800, 833, 844, 855, 866, 877, 888) generate 16.9 complaints per number on average
• Local numbers generate just 8.8 complaints per number
• Toll-free scam numbers account for 69,559 complaints from only 4,105 numbers

This means toll-free numbers are nearly twice as dangerous per number as local ones. Your blocking strategy should prioritize them.

Step 1: Turn On Silence Unknown Callers

This is the single most effective setting on your iPhone.

1. Open Settings
2. Scroll down and tap Phone
3. Tap Silence Unknown Callers
4. Toggle it ON

When enabled, calls from numbers not in your Contacts, recent outgoing calls, or Siri Suggestions go straight to voicemail. Since the vast majority of scam calls come from numbers you have never contacted, this blocks most of them instantly.

Important: Legitimate callers (doctors, delivery drivers) will still leave voicemails. Check your voicemail regularly after enabling this.

Step 2: Enable Your Carrier's Free Spam Filter

All major US carriers offer free call filtering:

These carrier-level filters catch known scam numbers before they even reach your iPhone's settings. They work alongside Silence Unknown Callers for layered protection.

Step 3: Block Specific Numbers

When a scam call gets through, block it permanently:

1. Open the Phone app
2. Tap Recents
3. Tap the i icon next to the scam number
4. Scroll down and tap Block this Caller
5. Confirm by tapping Block Contact

Based on our FTC data, the most-reported scam number in the US is (877) 419-6664 with 1,772 complaints. If you have received a call from this number, block it immediately.

Step 4: Filter Unknown Senders in Messages

Scam calls often come alongside scam texts from the same operation. Block both:

1. Open Settings
2. Tap Messages
3. Toggle Filter Unknown Senders to ON

This moves texts from unknown numbers to a separate "Unknown Senders" tab instead of your main inbox.

Step 5: Report Scam Calls to Build the Blocklist

Every report you file helps block scam numbers for everyone:

1. Forward scam texts to 7726 (SPAM) - works on all carriers
2. Report to the FTC at ReportFraud.ftc.gov
3. Use ScamVerify to check suspicious numbers at scamverify.ai/phone-lookup

The FTC database now contains over 1.5 million complaints covering 608,145 unique phone numbers. Your reports feed directly into this system.

What If These Settings Block Legitimate Calls?

If you are worried about missing real calls:

• Contacts always ring through even with Silence Unknown Callers enabled
• Recent outgoing calls ring through - if you called your doctor, their callback gets through
• Siri Suggestions ring through - numbers from your email, messages, and calendar
• All blocked calls go to voicemail - nothing is truly lost, just filtered

FAQ

Does Silence Unknown Callers block all scam calls?

It blocks most of them. Our data shows that the top 25 most-reported scam numbers are all toll-free numbers that would not be in your contacts. However, scammers who spoof local numbers may still appear as unknown callers going to voicemail.

Do I need a third-party call-blocking app?

For most people, the built-in iPhone settings plus your carrier's free filter are sufficient. Third-party apps add an extra layer of caller ID but are not required.

Will Silence Unknown Callers work if I'm waiting for an important call from an unknown number?

You can temporarily disable it in Settings > Phone > Silence Unknown Callers. Toggle it back on after you receive the expected call.