How to Block Calls From Unknown No Caller ID Numbers on iPhone

Key takeaways:

  • iPhone has built-in features to block unknown callers and send them directly to voicemail
  • Third-party apps offer additional spam call blocking capabilities
  • Carriers like AT&T and Verizon provide their own spam blocking services

Receiving calls from unknown numbers or those with no caller ID can be frustrating and even potentially dangerous. These calls are often from telemarketers, scammers, or robocallers trying to sell you something or steal your personal information. Fortunately, iPhone users have several options to block these unwanted calls and protect their privacy.

Using iPhone’s Built-in Features

Apple has included some basic call blocking features in iOS to help users avoid unwanted calls. The most effective built-in option is the “Silence Unknown Callers” feature, which was introduced in iOS 13. When enabled, this feature will automatically silence calls from numbers that are not in your contacts, recent outgoing calls, or Siri suggestions. These calls are sent straight to voicemail without your phone even ringing.

To enable “Silence Unknown Callers”:

  1. Go to Settings > Phone
  2. Scroll down and toggle on “Silence Unknown Callers”

Keep in mind that this feature will block all calls from numbers not in your contacts, so you may miss some important calls. However, the caller can still leave a voicemail, and you’ll be able to see the missed call in your recent calls list.

Another built-in option is to block specific numbers that you’ve identified as spam. To do this:

  1. Go to the Phone app and tap on the “Recents” tab
  2. Find the number you want to block and tap the “i” icon next to it
  3. Scroll down and tap “Block this Caller”

This will prevent that specific number from calling you again, but it won’t stop other spam calls from coming through.

Using Third-Party Apps

For more advanced spam call blocking, there are several third-party apps available on the App Store. These apps use constantly updated databases of known spam numbers to identify and block unwanted calls before they even reach your phone. Some popular options include:

  • RoboKiller: Automatically blocks spam calls and telemarketers, and even has a feature that wastes their time with pre-recorded messages.
  • Truecaller: Identifies unknown numbers and blocks spam calls and SMS messages. Also includes a reverse number lookup feature.
  • Hiya: Offers real-time spam detection and blocking, as well as caller ID and reverse phone lookup.

To use these apps, you’ll need to grant them access to your contacts and phone app. Some apps are free with ads, while others require a subscription for full features.

Carrier-Provided Spam Blocking

Many major cell carriers now offer their own spam blocking services to help protect their customers from unwanted calls. These services are often free or included with certain plans, and can be managed through the carrier’s app or website.

  • AT&T: Provides the AT&T Call Protect app, which automatically blocks suspected spam calls and allows you to create a personal block list.
  • Verizon: Offers the Call Filter app, which detects and filters spam calls, and provides caller ID and spam risk information.
  • T-Mobile: Includes the Scam Shield app, which identifies and blocks scam calls, and offers a second “proxy” number to use for online signups.

Check with your specific carrier to see what spam blocking options they provide and how to enable them on your iPhone.


Blocking calls from unknown or no caller ID numbers on your iPhone is an important step in protecting your privacy and avoiding unwanted interruptions. By using a combination of built-in features, third-party apps, and carrier-provided services, you can significantly reduce the number of spam calls you receive and have peace of mind knowing your phone is secure.


Will silencing unknown callers block calls from people I know?

If the person calling you is not in your contacts, their call will be silenced even if you know them. However, they can still leave a voicemail, and you’ll be able to see the missed call in your recent calls list.

Do I have to pay for third-party spam blocking apps?

Some apps offer basic features for free with ads, while others require a subscription or one-time payment for full functionality. Be sure to check the app’s pricing and features before downloading.

Can I block all calls from a specific area code?

iPhone does not have a built-in feature to block calls from a specific area code. However, some third-party apps may offer this capability.

Will blocking a number stop them from leaving me voicemails?

No, even if you block a number, they will still be able to leave you voicemails. However, you won’t receive a notification for the voicemail, and it will be sent to a separate “Blocked Messages” folder.

What should I do if I keep receiving spam calls even after blocking them?

If you continue to receive spam calls, you can report the numbers to the FTC’s National Do Not Call Registry and file a complaint. You can also contact your carrier to see if they offer additional blocking options or have any recommendations for stopping persistent spam callers.