Unknown numbers, annoying spam calls and SMS mailings have become a real problem for smartphone owners. According to Kaspersky, in 2023, every third Android user encountered fraudulent calls at least once a week. Fortunately, modern versions of the operating system offer several built-in protection mechanisms - from basic blocking through the call log to advanced filters at the carrier level.

In this article we will analyze all available methods for blocking unknown callers - from standard Android functions to hidden manufacturer settings (Samsung Knox, MIUI Security) and third-party applications with artificial intelligence. We will pay special attention to the nuances: what to do if the number is hidden, how to block entire ranges of codes and why some methods may not work on older versions of Android (below 8.0 Oreo).

Important: blocking only works for incoming calls and messages. If the unknown subscriber is already contacted you via instant messengers (WhatsApp, Telegram), you will need separate settings in each application - we will also consider them.

1. Standard blocking via call log

The easiest way is to use the built-in Android tools. The method works on all smartphones, regardless of the manufacturer, but the interface may vary slightly. differ.

Instructions:

  1. Open the application Phone (handset icon).
  2. Go to section Call log (or History).
  3. Find the number you want to block and click on it.
  4. In the window that opens, select Block / Block number (on Samsung — Details → Block).
  5. Confirm the action in the dialog box.

On some firmware (for example, ColorOS from Oppo/Realme) the path will be others: Settings → Blocking and protection → Black list. If you don’t find the option, use the search in the settings (magnifying glass icon in the upper right corner).

The number is not saved in contacts|

The "Not" mode is enabled disturb" for unknown people|

The "Phone" application on Google Play has been updated|

Operator settings have been checked (see section 3)

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⚠️ Attention: On Android 7.0 and below, the built-in blocking may not work for hidden numbers (Unknown subscriber or Private Number). In this case, use the methods from section 4.

After blocking, the subscriber will not be able to reach you - his call will be automatically dropped, and SMS notifications about the missed call from the blocked number will not be displayed. will be.

2. Blocking through Android settings (for hidden numbers)

If you are bothered by calls from hidden numbers (Unknown caller, Number hidden), the standard method from section 1 will not work. The system setting will help here. call filtering:

Steps:

  1. Open Settings → Google → Services on phone.
  2. Select Calls and SMS → Filter spam and calls.
  3. Activate the switch Filter spam calls.
  4. Enable the option Block hidden numbers (if available).

On smartphones Samsung the path is different: Settings → Options → Blocking calls and messages → Block unknown/hidden numbers. U Xiaomi a similar option is hidden in Security → Blocking → Settings → Block hidden numbers.

Manufacturer Path to settings Does it support hidden numbers
Google Pixel Settings → Calls → Spam filter Yes
Samsung Settings → Features → Call blocking Yes (on One UI 4.0+)
Xiaomi/Redmi Security → Lock → Settings Yes (on MIUI 12+)
Huawei/Honor Phone → ... → Settings → Lock No (manual only)

On devices with Android 12 and later, Google automatically blocks known spam numbers through the Google Play Protection database. To check if this feature is enabled, go to Settings → Google → Security → Google Play Protection → Settings → Scan device for security threats.

Once a day or more often|

Several times a week|

Rarely (once a month)|

Never encountered-->

3. Blocking through a telecom operator

Mobile operators (MTS, Beeline, MegaFon, Tele2) offer their own spam filtering services. Their advantage is that blocking works even if the phone is turned off or is outside the network coverage area.

How to connect:

  • 📱 MTS: send an SMS with the text BLOCK1 to number 111 (free of charge) - activate the "Spam Protection" service through your personal account. office.
  • 📱 Beeline: dial *110*789# and follow the instructions. An alternative is the Antispam service in the My Beeline application.
  • 📱 MegaFon: activate "Spam Protection" in your personal account or via USSD command *105*400#.
  • 📱 Tele2: send an SMS with the text STOP SPAM to the number 4040.
⚠️ Attention: Operator services can block not only spam, but also legitimate calls (for example, from banks or delivery services) Before activating, check the list of blocked categories in your personal account.

The advantage of this method is centralized blocking: the number will be blocked at the network level, and not just on your device. Disadvantage - operators update the database of spam numbers with a delay (sometimes up to 72 hours).

What to do if the operator does not block number?

If calls continue after connecting the service, contact the operator's support and request manual blocking of the number by IMEI. To do this you will need:

1. Provide the last 5 digits of the number from which they are calling.

2. Indicate the date and time of the last call.

3. Confirm your identity (passport data or code word).

The operator is obliged to block the number within 24 hours according to the order of the Ministry of Telecom and Mass Communications No. 363 of 2019.

4. Third-party blocking applications

If the built-in Android tools do not cope, specialized applications will come to the rescue. They offer advanced functions: blocking by keywords in SMS, creating white lists, analyzing calls using AI.

Top 5 proven applications:

  • 🛡️ Truecaller —base of 500 million numbers, spam identification. in real time. Minus: requires access to contacts.
  • 🔒 Hiya — blocks robocalls and scammers, integrates with a system phone. Free version is limited to 20 blocks per month.
  • 📵 CallApp — call recording, geolocation blacklists, dual-SIM support.
  • 🚫 Should I Answer? — open source, no ads, works offline. Ideal for privacy.
  • 🤖 SMS Shield — specializes in SMS spam, filters messages by templates (for example, “you won a prize”).

How to install and configure (using an example Truecaller):

  1. Download the application from Google Play.
  2. Launch and allow access to Contacts, Call Log and SMS.
  3. To the menu Blocking add numbers manually or activate automatic filtering.
  4. Enable the option Block hidden numbers in the settings.
⚠️ Attention: Applications like Truecaller upload your contacts to their servers to form a database. If privacy is critical, use offline solutions like Should I Answer?.

For maximum protection, combine the Android system lock with one of these applications. For example, Hiya can filter robocalls, and built-in settings can block hidden numbers.

💡

Before installing a third-party application, check reviews for the last 3 months. Some anti-spam services begin to show intrusive advertising after updates.

5. Blocking in instant messengers (WhatsApp, Telegram, Viber)

Unknown subscribers can harass you not only through calls, but also through instant messengers. Each of them has its own blocking mechanisms:

WhatsApp:

  1. Open a chat with an unwanted contact.
  2. Click on the three dots in the upper right corner → More → Block.
  3. Confirm the action. The contact will be removed from your list and will not be able to write/call.

Telegram:

  • Open the user profile.
  • Click on the three dots → Block.
  • Enable the option Report spam, if it's a scammer.

Viber:

  1. Go to chat with the contact.
  2. Tap his name → Information → Block.
  3. Activate Hide chatso that it does not appear in the list.

Important: in Telegram a blocked user will not see the blocking notification, but will be able to write to you in group chats. In WhatsApp i Viber the blocking is complete - the contact will not be able to see your online status or read messages.

💡

Blocking in instant messengers does not affect phone calls and SMS. To completely cut off an unknown caller, use a combination of methods from this article.

6. Advanced methods: blocking by number range

If you are inundated with calls from numbers in one region or operator (for example, +7 9xx xxx-xx-xx), you can block an entire range. To do this you will need:

  • 📱 root access (for older versions of Android).
  • 📱 ADB commands (for new versions without root).
  • 📱 Specialized applications (for example, Call Blocker).

Method with ADB (without root):

  1. Install Android SDK Platform-Tools on PC.
  2. Connect your phone via USB and activate USB debugging in developer settings.
  3. Enter a command to block the range (example for 911* numbers): 
    adb shell content insert --uri content://call_log/calls --bind number:s:"911%" --bind type:i:3

through the app Call Blocker:

  1. Download the application from Google Play.
  2. Go to section Blocking rules → Add rule.
  3. Select Block by mask and enter a template (for example, +7926*** for all numbers MTS Moscow).
⚠️ Attention: Blocking ranges can lead to missing important calls (for example, from taxi services or couriers). Use this method only if you are sure of the sources of spam.

For corporate users there is a solution from Google — Android Enterprise with blocking policies at the organization level. This is relevant if spam calls are received on work numbers.

7. What to do if blocking does not work

Sometimes, even after all the settings, spam calls continue to arrive. solutions:

Problem Possible cause Solution
The number is not blocked The subscriber uses Caller ID substitution (spoofing) Enable blocking of all hidden numbers (section 2)
Calls come from different numbers Spambot number generator Use applications with AI filtering (Hiya)
The blocking is reset after reboot The system application "Phone" has failed Clear the application cache in Settings → Applications
SMS continues to arrive The operator does not support filtering SMS Install SMS Shield or analogs

If the problem is spoofing (number substitution), when scammers show random numbers instead of the real Caller ID, only blocking all incoming calls except contacts from the address book will help. data-i="246">spoofing

  1. Go to Settings → Security → Call blocking.
  2. Activate the option Only contacts (on Samsung — Reject calls from unknowns).

The disadvantage of this method is that you will miss calls from new contacts (for example, from work or from delivery services). Solution: temporarily disable filtering when you are waiting for an important call.

FAQ: Frequently asked questions about blocking. numbers

Is it possible to find out who called from a blocked number?

No, after blocking, information about the call is not saved in the log. However, if the number is not hidden, you can find it in the history to of blocking or through services like Truecaller (if it is in their database).

Will the subscriber know that he has been blocked?

Depends on the blocking method:

  • 📱 When system blocking (section 1) - the subscriber will hear short beeps or a voice message "Subscriber unavailable."
  • 📱 When blocked through an operator, the call may be dropped without beeps.
  • 📱 In instant messengers (WhatsApp, Telegram) - the user does not receive a notification, but may suspect blocking based on indirect signs (for example, he does not see your “online” status).
How to unblock a number if you change your mind?

Unblocking methods:

  • 📱 System blocking: Settings → Calls → Black list → uncheck the number.
  • 📱 Through the operator: send an SMS with the text UNBLOCK [number] to the short number of your operator (check in your personal account).
  • 📱 In messengers: open the user profile → Unblock.

If you don’t remember the number, check the blocking history in the application you used (for example, in Truecaller there is a section Blocked).

Is it possible to block all international calls?

Yes, but not through the standard Android settings Options:

  1. Use the application Call Blocker with the rule Block +[country code] (for example, for the USA, for Turkey). against international spam"). +1 for USA, +90 for Turkey).
  2. Activate the service from your operator (for example, MegaFon there is "Protection against international spam").
  3. Set up Do not disturb with the exception for local numbers (Settings → Sound → Do not disturb → Allow calls from → Contacts).

Please note: this will block all foreign calls, including legitimate ones (for example, from foreign colleagues or support services).

Why does the number still ring after blocking?

Probable causes and solutions:

  • 🔄 The subscriber changes the number: spammers often use number generators. Solution - block by the first digits (for example, +7999***).
  • 📡 Network problems: sometimes operators reset the filtering settings. Check the status of the service in your personal account.
  • 🤖 Robocall with Caller ID substitution: enable blocking of all hidden numbers (section 2).
  • 📱 Application failure: clear the system application cache Phone or reinstall antispam service.

If the problem persists, try combining methods: system blocking + operator + third-party application.