If you do not want to answer calls of certain subscribers, you can block their phone numbers in the list of your contacts on the iPhone (detailed instructions on how to use the “Blacklist on the iPhone”).

However, it would be great to go even further and block calls from all unknown subscribers and those whose number cannot be identified.

As a rule, callers from the “No subscriber ID” or “Unknown” numbers are robots (of course, there are exceptions), employees of marketing departments trying to sell you something, etc., therefore, getting rid of their annoying calls was would be quite good.

Below we will tell you how to block all unknown and undetectable numbers on the iPhone.

Please note that this method should not be used if your loved ones often call from someone else’s numbers.

ATTENTION!!! Using it, you will receive calls only from subscribers from your contact list, so you risk missing an important call.

How to block on iPhone all calls from unknown and undetectable (hidden) type “No subscriber ID” or “Unknown” numbers.

How to Block all Calls from Unknown ID on iPhone?

Read more: How to Unblock a Caller on your iOS Device?

This method is not a standard blocking of subscribers on the iPhone, but an ingenious use of the Do Not Disturb mode and the list of contacts. So, how it works:

  • Open the “Settings” or “Quickslide menu” on your iPhone and select the “Do Not Disturb” feature;
  • Slide the switch against the “Do Not Disturb” option to the “On” position;
  • A crescent will appear on the screen in the status bar (where the clock is), after which the device will make absolutely no sounds;
  • Click on “Call Admission” and you will see two options. Select “Favorites” if you only want to receive calls from your favorite contacts. This option is suitable for users who have added the numbers of all friends and family members to Favorites (add the necessary contacts to the Favorites) and never receive calls from other numbers;
  • Choose the option “All Contacts” or a group of contacts (we told how to create groups of contacts on iPhone here and here), then you will receive calls from all subscribers from the contact list. However, those who have not been added to your address book will not be able to call;
  • Before using this method, carefully consider whether someone will call you on an important issue from a number that is not on the contact list. If you are sure of your decision, feel free to close the “Settings” and enjoy the silence.

Whereas the callers in your handset will always be “busy”.


The Do Not Disturb feature activates a completely silent mode on the iPhone and mutes not only calls, but also notifications. It is best to set the clock when it will be activated automatically. For example, every night at a certain time, the iPhone will go into silent mode, and then return to normal every morning. Of course, you can configure the function so that the smartphone remains silent around the clock.

It is also recommended to activate the possibility of repeated calls in the “Do Not Disturb” mode. If someone calls twice within three minutes, the call will not be silenced. Users who do not have a contact list or “Favorites” should not use the method described above, otherwise they will not receive calls from anyone at all.

It’s the best time to ask questions and give us your feedback in comments.


Hi there! My Name is Vincent Lago! My goal is to share insightful reviews, guides, and manuals for people looking to know more about current solutions for Apple hardware and OS. I have years of technological background knowledge including owning a custom iMacs & PCs which was using for different types of business. And now, I want to share my experience with you.

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