You don’t need me to tell you how annoying robocalls or marketing calls are. We get them all the time and no matter how many call centers are taken down, more spring up to bombard us with more annoying calls. One frustration to add to the list is when these callers use the private number function to hide their real phone number. You can block calls from private numbers on Android though.
Some call centers don’t want you to know where they are calling from or be able to identify them from their number. Some don’t seem to know their number comes up as private when they call you, or at least profess ignorance when challenged. Either way, you want to be able to block these calls as easily as you can calls with numbers.
This tutorial will show you how.
Blocking calls from private numbers
Both Android and iPhone have the ability to block calls from private numbers, or any number come to that. I’m talking about Android in this tutorial though and will cover iPhone another time.
Blocking private numbers isn’t perfect. The setting is a blanket ban on all private numbers so friends or family who use withheld numbers will be blocked too. As blocking is done on the handset and not on the network, this is the only way to do it.
When you use *67 to hide your number, your phone sends the request to the network along with the digits you dial. The entire message transits your cell provider’s network until the final switch and the caller ID is withheld at that final point. This is to enable billing for the call. As the caller ID is not sent to the receiving phone, Android cannot look behind the private number message to block the number attached to it. That’s why you can only blanket block private numbers.
Here’s how to block calls from private numbers in Android:
- Open the dialer app on your phone.
- Select the three dot menu icon in the top right.
- Select Settings and Block Numbers.
- Select Block Unknown Callers from the top of that page.
Even though the text is different, this setting will effectively block private numbers. If you know of friends or family who withhold their caller ID when calling, it might be a good idea to warn them you have this set up.
Stopping persistent private callers
If you are constantly called by private numbers and the above doesn’t work for you, it is possible to request the network blocks the call. As the caller ID is presented to your cell network to help call routing and billing, the network can put a block on the call for you if you raise a nuisance call complaint.
Different providers handle this in different ways but they should have a mechanism for blocking persistent callers at the network level. Depending on your provider, it is worth contacting them directly and requesting a network block on the caller. You will need a couple of examples of the call, with an accurate date and time so the network can trace the call. They should then be able to place a block on that number and stop them bothering you.
Again, different cell providers handle this in different ways so check yours to see what is possible.
Block unknown numbers in Android
An unknown number is different from a private number. A private number withholds their caller ID and shows Private Number on your phone display. An unknown number will show a number you don’t recognize. These are easier to block as your phone can identify the caller and filter as appropriate.
The easiest time to block a number is after receiving a call from it.
- Open your dialer app and select the number that just called.
- Select the Details icon underneath.
- Select the three dot menu icon in the top right of the new window.
- Select Block Number.
From that moment on, your phone will automatically reject calls from that number. It won’t ring or notify you of the call but they will appear in your calls list as blocked.
There’s an app for that
There are a bunch of apps that say they can block calls for you and can perform various caller identification tasks. Android and iPhone both have call rejection built in so these are of varying value. If unknown call blocking isn’t working out for you it might be worth checking this page on the Google Play Store. 
It has a list of apps offering a range of features including blocking private callers, unknown callers, blocking spam SMS and more. If the built-in features aren’t hitting the spot, maybe one of these will.