How to block all unknown incoming calls on Android: a complete guide

Spam calls and fraudulent numbers have become a real scourge of modern smartphones. According to data Kaspersky, in 2026, every third user Android faced telephone phishing attempts at least once a week. Unknown numbers are not only annoying, but also pose a real threat: from identity theft to connecting paid services without your consent.

Fortunately, Android offers several built-in mechanisms for blocking unwanted calls - from simple blacklists to advanced filters based on artificial intelligence. In this article we will analyze all available methods: from standard functions Google Phone to hidden manufacturer settings (Samsung Knox, MIUI Security) and third-party applications with advanced capabilities. You will learn how to set up automatic blocking of all calls from unidentified numberswithout losing important calls from banks or delivery services.

1. Built-in Android tools: Google Phone and Contacts

Basic call blocking functions are available in the standard app Phone (or Google Phone) on most devices. This method works on “clean” Android (for example, Google Pixel, Nokia, Motorola) and some models of other brands. The main advantage is that you do not need to install additional apps.

To enable filtering of unknown numbers:

• 📱 Open the application Phone and click on the three dots in the upper right corner.
• ⚙️ Select Settings → Spam and call blocking.
• 🔒 Activate the option Filter spam calls.
• 🌐 Turn on Show ID and spamto see warnings about suspicious numbers.

To completely block all unknown numbers:

1. Go to Settings → Blocking numbers.
2. Select Unknown in the list of call types.
3. Confirm the action - now all calls from numbers not saved in Contactswill be automatically deviate.

⚠️ Attention: On some firmwares (for example, One UI from Samsung or ColorOS from Oppo) the path to the settings may differ. If you do not find the indicated items, check the section Additional settings in the application Phone.

2. Manufacturer features: Samsung Knox, MIUI, EMUI

Smartphone manufacturers often add their own security solutions. These tools can be more effective than standard ones because they are integrated at the firmware level. Let's look at the most common brands:

Brand	Blocking function	Where to find	Features
Samsung	Smart Call	Settings → Functions for convenience → Smart Call	Uses the database Hiya to identify spam, blocks fraudulent numbers automatically.
Xiaomi	Call blocking	Security → Call blocking	Allows you to add numbers to the blacklist by regular expressions (for example, all numbers with the prefix +375).
Huawei	Harman Kardon Audio + Blocking	Phone → Settings → Blocking and filtering	Integrated with the service Truecaller (requires registration).
Realme/Oppo	Safe numbers	Settings → Privacy → Safe numbers	Filters calls by geolocation and spammer database.

For example, on devices Samsung c One UI 5.0+ function available Blocking calls from unknown in the menu Phone settings → Blocking numbers. Here you can:

• 📵 Block all numbers not saved in Contacts.
• 🔍 Add exceptions for certain prefixes (for example, +7 800 for toll-free numbers).
• 📊 View the log of blocked calls.

⚠️ Attention: On smartphones Xiaomi s MIUI 14+ when blocking unknowns is activated numbers automatically turns on the function Call recording for all incoming calls. Disable it in Settings → Call recordingif it violates your privacy.

Make sure you have the latest version firmware

Make a backup copy of your contacts

Check if you are using a dual-SIM (settings may be duplicated)

Disable VPN (some blocking functions do not work via VPN)-->

3. Third-party applications: Truecaller, Hiya, Should I Answer?

If the built-in functions are not enough, third-party applications offer advanced features: databases of spam numbers, analysis of caller behavior and even blocking by geolocation. The most popular solutions:

1. Truecaller (Play Market)

• 🌍 Database of more than 300 million numbers, updated in real time.
• 🤖 Automatic identification of spam and scammers.
• 📊 Statistics on the most active spammers in your region.
• ⚠️ Requires registration and access to contacts (can be disabled in settings).

2. Hiya: Caller ID & Block (Play Market)

• 🛡️ Blocks robocalls and number scanners.
• 📱 Lightweight application (less than 10 MB).
• 🔍 Shows the reputation of the number before the call is answered.

3. Should I Answer? (Play Market)

• 📊 Color marking of numbers: green - safe, red - spam.
• 🌐 Works offline (the database is updated when connected to the Internet).
• 🔒 There is no mandatory registration.

For maximum protection, it is recommended:

1. Install Truecaller for the global database of numbers.
2. Additionally use Hiya to block robocalls.
3. In the settings of both applications, activate the option Block all unknown numbers.

⚠️ Attention: Some banks and delivery services (for example, SDEK or Boxberry) may call from dynamic numbers that applications will consider spam. Add such numbers to Exceptions after the first successful call.

How do modern scammers bypass blocking?

Spamers often use “spoofing” (number substitution), when a call allegedly comes from your own number or a well-known bank (for example, +7 900 123-45-67 instead of the real one +375 29 123-45-67). To protect yourself:

1. Never call back unknown numbers, even if they look like yours.

2. Enable the "Show original number" option in your phone settings (if available).

3. Use applications with a number authentication function (for example, Truecaller Premium).

4. Blocking through a telecom operator: MTS, Beeline, MegaFon, Tele2

Russian operators provide free and paid services for filtering spam. These services work at the network level, so they block calls even before they reach your phone. Key offers:

Operator	Service	Cost	How to connect
MTS	Spam protection	Free	Send SMS with text PROTECTION to number 111.
Beeline	Antispam	Free	Dial *110*789# and call.
MegaFon	Spam filter	30 rub/month	Send SMS with text 1 to number 0500.
Tele2	Spam blocking	Free	Dial *155*1# and call.

Advantages of operator blocking:

• 📵 Works even if the phone is turned off or in airplane mode (calls are blocked at the network level).
• 🔄 Updated databases of spam numbers from the operator.
• 📊 Ability to view statistics of blocked calls in your personal account.

Disadvantages:

• ⚠️ Not all operators block 100% of spam (especially international numbers).
• 📱 Settings may be reset when changed SIM cards.
• 💰 Some services are paid (for example, from MegaFon).

⚠️ Attention: If you use a virtual operator (for example, Tinkoff Mobile or SberMobil), spam blocking services may not be available. Check with your provider's support for details.

5. Advanced methods: ADB, Tasker, automation

For Advanced tools are available for experienced users who want complete control over incoming calls. These methods require technical skills, but allow you to configure blocking with maximum flexibility.

1. Blocking via ADB (without root)

By using Android Debug Bridge you can block incoming calls from unknown numbers at the system level. data-i="203">Activate

1. Activate Developer mode (click 7 times on Build number in the phone settings).
2. Enable USB debugging in the developer menu.
3. Connect the phone to the PC and run the command:

   adb shell settings put global block_unknown_callers 1

4. Reboot the device.

2. Automation with Tasker

Application Tasker allows you to create rules for blocking calls based on various criteria (time of day, geolocation, number prefix). Example profile:

• 📱 Condition: Incoming call from a number not located in Contacts.
• ⏰ Time: From 22:00 to 8:00 (night mode).
• 🔕 Action: Reject the call and send an SMS with the text "Calls are accepted from 8:00 to 22:00."

3. Blocking by regular expressions (for Xiaomi)

On smartphones Xiaomi in the menu Security → Call blocking you can add mask rules. data-i="227">Security → Call blocking

• Block all numbers from the prefix +375 (Belarus): enter ^\+375.
• Block numbers with repeating numbers (for example, 111111): enter (\d)\1{5,}.

⚠️ Attention: ADB commands and Tasker settings may conflict with the firmware. Before experiments, create a backup via Settings → System → Backup. On some devices (for example, Samsung s) using ADB may reset the counter Knox) using ADB can reset the counter Knox Warranty Voidvoids the warranty.

6. How to avoid false positives: exceptions and white lists

The main problem of automatic blocking is the risk of missing an important call. To avoid this, configure exceptions (white lists) for:

• 🏦 Banks and payment systems (numbers usually start with +7 800 or +7 495).
• 🚚 Delivery services (SDEK, Boxberry, Russian Post).
• 🏥 Medical institutions and emergency services.
• 📦 Online stores (for example, Ozon, Wildberries).

How to add a number to the white list:

On Google Phone:

1. Open Phone → Settings → Blocking numbers.
2. Select Add exception.
3. Enter a number or select from Contacts.

In Truecaller:

1. Go to Settings → Blocking.
2. Select Exceptions.
3. Add a number or range (for example, +7800*).

In the operator settings:

Most operators have the ability to manage white lists via USSD commands or personal account. For example, MTS:

• Send an SMS with the text ALLOW 79123456789 to. number 111.
• Or add the number in your personal account on the operator's website.

How to find out who called from blocked numbers?

If you missed an important call, but the number was blocked, check:

1. Call log in the application Truecaller (section "Blocked").

2. Extended log in Settings → Applications → Phone → Memory → Call log (root required).

3. Notifications from the operator (some providers send SMS about missed blocked calls).

7. Additional measures: two-factor authentication and account protection

Blocking calls is only part of the protection. telephone numbers for hacking accounts (for example, through password recovery via SMS). To minimize risks:

1. Disable password recovery via SMS

• B Google Account: go to Security → Account login → Two-step authentication and select Authenticator application instead of SMS.
• B VKontakte: in the security settings, disable the option Recovery by phone number.

2. Use virtual numbers for registration

Services like Google Voice or Numo allow you to create a temporary number for registering on sites. Main advantages:

• 📵 Your real number will not be included in spammers' databases.
• 🔄 You can change your virtual number at any time.
• 📊 It's easy to track who sold your data (by call sources).

3. Set up notifications about suspicious activity

B Google Account activate the option Security Alerts (Security → Security Settings → Alerts). about:

• Login attempts from a new device.
• Changes in recovery settings.
• Suspicious actions (for example, bulk SMS mailing).

⚠️ Attention: If you use WhatsApp or Telegram for business correspondence, disable linking your account to the number phone. In the messenger settings, select the option Use email to log in (if available). This will protect against SIM-swap attacks, when scammers transfer your number to their SIM card.

FAQ: Frequently asked questions about blocking calls

🔹 Is it possible to block all incoming calls except contacts?

Yes, this is possible in several ways:

1. B Google Phone: Settings → Blocking numbers → Unknown.
2. On Samsung: Phone settings → Block numbers → Block unknown numbers.
3. Through Truecaller: enable the option Block everything except contacts in the blocking settings.

Please note: some system numbers (for example, from an operator) may still pass through.

🔹 Why does blocking not work on a dual-SIM phone?

On devices with two SIM cards, blocking settings can be duplicated for each card separately. Check:

• In Google Phone: switch to the second SIM in the top menu and set up a lock separately.
• On Xiaomi: in Settings → SIM cards and mobile networks select SIM and set up a lock for it.

Also make sure that both SIM cards support blocking services from the operator.

🔹 How to unblock a number if it was blocked by mistake?

Methods depend on the blocking method:

• Built-in blocking: Go to Settings → Blocking numbers and remove the number from the list.
• Truecaller/Hiya: Open the blocked call log in the application and click Unblock.
• Operator blocking: Send a USSD command (for example, for MTS: *111*789#) or contact support.

If the number was blocked by a regular expression (for example, on Xiaomi), delete the corresponding rule in Security → Call blocking.

🔹 Is it possible to block calls by geolocation (for example, from another region)?

Yes, but this will require third-party applications:

• Truecaller Premium: allows you to block numbers by country or region.
• Call Control: supports geo-filtering by area code.
• Tasker: you can create a rule that will reject calls if your current location does not match the area code of the number.

Please note: geo-blocking may give false positives if the call comes through a virtual PBX (for example, from a call center bank).

🔹 What to do if after blocking you stop receiving SMS?

This is a common problem when using aggressive filters (for example, in Truecaller or via ADB). Solutions:

1. Check whether SMS from unknown numbers are blocked in the messenger settings.
2. In Truecaller disable the option Block SMS from spammers (Settings → Blocking → SMS).
3. If you used ADB, run the command:

   adb shell settings put global block_unknown_callers 0

   and restart the phone.

For important SMS (for example, from a bank), add sender numbers to the white list.