How to Block Unknown Callers on iPhone: The Complete Call Filtering Guide for iOS 18 and 26

Tired of constant calls from unknown numbers disrupting your day? iPhone’s call filtering feature automatically silences calls from unknown callers and sends them to voicemail, letting you stay focused without missing important calls from people you know.

What is iPhone Call Filtering?

Call filtering is a built-in iPhone feature that uses Siri intelligence and community-sourced spam identification to handle calls from unknown numbers. Unlike blocking, which completely prevents contact, filtering routes unknown callers to voicemail while keeping your phone silent.

iPhone offers two distinct filtering options:

Silence Unknown Callers - This silences calls from unknown numbers (no audible ring) and sends them directly to voicemail. These calls still appear in your Recents list so you can see who called.

Filter Unknown Callers - This moves unknown caller missed calls and voicemails to a separate Unknown Callers list, keeping them completely out of your main call history.

The feature has been available since iOS 13 and continues to improve through iOS 18.7.2 and iOS 26.1. Apple’s system is smart enough to let calls through from saved contacts, people you’ve recently called, numbers in your message history, and contacts Siri recognizes from your Mail and Messages apps. Emergency calls also temporarily bypass filtering for 24 hours after you place an emergency call.

Current as of: iOS 18.7.2 and iOS 26.1 (2025)

Source: Apple Support - Manage unknown callers on iPhone

Why Use Call Filtering?

• Reclaim Your Peace: Stop answering unknown calls out of obligation. Unknown callers go straight to voicemail, keeping you focused on what matters.
• Never Miss Important Calls: Legitimate callers—from your doctor’s office, bank, or friends—ring through normally. Your phone only silences actual unknown numbers.
• Built-In Spam Protection: The feature automatically learns from community reports and Siri’s intelligence to identify likely spam calls before they reach you.
• No Special Setup Required: Call filtering works immediately after you enable it. No additional apps or complicated configurations needed—it’s all in your iPhone’s Settings.

Things to Consider Before Enabling

• International Calls: Unknown international callers will be silenced if filtering is enabled. If you regularly receive important calls from abroad, consider saving those numbers to your Contacts first.
• Private and Restricted Numbers: Callers who hide their caller ID cannot be individually managed through iOS call filtering alone. Some carriers offer Anonymous Call Rejection at the network level (check with your provider), or you can use third-party apps like Truecaller, RoboKiller, or Hiya for more advanced filtering.
• Legitimate Callers May Be Filtered: Occasionally, calls from businesses or services you interact with might be filtered as unknown. Check your voicemail regularly during the first week to catch any missed important calls, then add frequently-calling numbers to your Contacts.

How to Enable Call Filtering on Your iPhone

The setup process varies slightly depending on your iOS version, but the core steps are the same. Follow the instructions for your iOS version:

For iOS 18 and iOS 18.7.2:

1. Open the Settings app on your home screen (gray gear icon).

2. Scroll down to the bottom of the Settings screen and tap Apps.

3. Tap Phone (or FaceTime if you want to filter FaceTime calls).

4. Tap Call Filtering.

5. Toggle Silence Unknown Callers to ON (the switch turns green).

6. (Optional) Toggle Filter Unknown Callers to ON for additional filtering that removes unknown calls from your Recents list entirely.

7. Verify the toggles are green, confirming your settings are active.

For iOS 26 and iOS 26.1:

1. Open the Settings app on your home screen.

2. Scroll down and tap Apps.

3. Select Phone (or FaceTime).

4. Tap Call Filtering.

5. Enable Silence Unknown Callers by toggling it ON (switch turns green).

6. Optionally enable Filter Unknown Callers for stronger filtering.

7. Confirm both toggles are green.

Important: Add Critical Numbers to Your Contacts

To ensure important callers always reach you, save their numbers to your Contacts:

8. Open the Phone app and go to Contacts.

9. Tap the + button to add a new contact, or tap an existing contact to edit it.

10. Enter or update the phone number and tap Save.

Contacts always bypass call filtering and will ring through normally, even if you don’t answer frequently.

Checking Your Voicemail

Filtered calls go to voicemail, so check regularly to catch any legitimate callers:

11. Open the Phone app and tap the Voicemail tab (bottom right).

12. Review voicemails from unknown callers. If any are important, save that number to your Contacts for future calls.

Source: Apple Support - Manage unknown callers, 9to5Mac - iOS 18 Settings changes

Troubleshooting: When Call Filtering Isn’t Working

Still receiving calls from unknown numbers?

Try these troubleshooting steps in order:

1. Restart Your iPhone: Press and hold the Side button and either volume button, then drag the Power Off slider. Wait 30 seconds, then turn it back on. This refreshes your phone’s systems and often resolves filtering issues.

2. Check Your iOS Version: Go to Settings > General > Software Update and install any available updates. Call filtering improves with each iOS release, and you may be running outdated software.

3. Disable Do Not Disturb: Check if Do Not Disturb is also enabled. Go to Settings > Focus > Do Not Disturb and turn it off if active. Having both enabled can cause unexpected behavior.

4. Uninstall Conflicting Apps: If you have third-party call filtering apps installed (RoboKiller, Truecaller, Hiya, etc.), temporarily uninstall them. These apps sometimes conflict with native iOS filtering. If calls work better without them, contact the app developer or switch to native iOS filtering.

5. Refresh Your iCloud Settings: Sometimes call history syncing issues interfere with filtering. Go to Settings > [Your Name] > Sign Out, wait 30 seconds, then go back and tap Sign In to re-authenticate your account.

6. Check Your Carrier Settings: Ask your carrier if they offer additional call filtering at the network level, or if there are carrier-specific settings you need to enable.

If issues persist after these steps, contact Apple Support with details about which calls are getting through unexpectedly.

Sources: Apple Community Support Discussions, Tenorshare - iPhone Call History Solutions

Enabling call filtering on your iPhone puts you in control of your phone experience, letting important calls through while silencing spam and unknown callers. Give it a week to learn your calling patterns, regularly check voicemail for legitimate callers, and adjust by adding important numbers to your Contacts. Your phone should work for you—not interrupt you.