Written by Michael Paulyn
Published on April 2, 2024

What is no caller ID?

No caller ID is when you receive a call but the caller deliberately hides their phone number from you. While this could be a legitimate call, it could also be malicious — such as a tech support scam, student loan scam, vishing attack, or an unwanted telemarketing call.

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    How to trace a no caller ID phone call

    To trace a call from an unknown number, use star codes like *69 and *57, contact your phone company directly, or use specialist third-party apps. You can then call the unknown number back or block it.

    Before you use tools and services to unmask your caller, check if they’ve left a voicemail. But don’t call a number provided in a voicemail unless you’re certain it’s genuine — it could be a scam and lead to unwanted charges on your phone bill.

    Figure out an unknown number with *69

    Dialing *69 is a simple way to find out an unknown caller’s number for free from your iPhone, Android, or landline. This service has been available for decades in the US and still works today.

    Here’s how to trace an unknown number using the *69 service:

    1. Dial *69 on a mobile or landline. On some devices, you may then have to press the Call button.

      The iPhone keypad with *69 dialled and the Call button highlighted.
    2. You will be told the number of the last person to call you.

    Once you know the unknown number, you can then check if it’s safe to call them back. A quick Google search of an unfamiliar number can help you decide whether to block the caller.

    Identify malicious callers with *57

    If you receive a threatening or harassing call you can dial *57. As soon as you’ve hung up on the threatening call, dial *57 — this will send the caller’s information to the service provider. Make a note of the date and time, then contact your local law enforcement agency. They will be able to get the details from the service provider. Note that *57 is not always free.

    Here’s how to use the *57 in the US:

    1. Dial *57. On some devices, you may then need to press the Call button.

      How to trace a no caller ID after you receive a threatening phone call.
    2. Listen to the recording and follow the instructions.

    Contact your phone company

    Another way to find out who’s behind a call with no caller ID is to contact your phone service provider. They may have their own tracing services or be able to provide more information than you can get from dialing *69.

    These services are different depending on each provider and may cost additional fees, so check before using a specific service or feature.

    Use a third-party app

    There are also third-party apps that you can use to track unknown numbers. These tools may offer limited free versions but will also have additional paid features for enhanced call-blocking and blacklisting.

    Here are two of the most popular apps for identifying unknown caller IDs on iOS and Android:

    • TrapCall. After you decline an unknown call, the app will call you with the unmasked number. You can then block the number if needed. It also includes other features like automatic blocking of robocalls.

    • TrueCaller. This app reveals unknown caller IDs and blocks spam calls. You can also send and receive texts using the app.

    Report scam calls to the FTC

    The Federal Trade Commission is a US government agency that looks after the interests of American consumers. There are two ways to report a scam to the FTC:

    • Visit the FTC’s Report Fraud page and follow the instructions to file a report.

    • Call 1-877-FTC-HELP (382-4357).

    Reporting your call to the FTC will allow them to investigate and potentially prosecute scammers. Reporting scams also helps the FTC build a clearer picture of the threat landscape, helping to identify patterns in scammers’ behavior.

    Silence or block unknown caller IDs

    To silence or block unknown caller IDs, you can use the Silence Unknown Callers feature on iPhone or the Filter Spam Calls toggle in the Android Settings menu. Both are free features that are part of their respective operating systems.

    Most iOS and Android phones also include broader call-blocking features. Third-party Android and iOS security apps can also be used to increase the range of tools available.

    On iPhone

    Apple’s iOS includes a specific feature that will silence calls from every unknown number. It then sends the call to voicemail so legitimate callers still have the chance to leave a message. To find the data and time of the call, check your Recents list.

    Here’s how to block unknown callers on iPhone using the Silence Unknown Callers feature:

    1. Go to Settings > Phone.

       To silence unknown callers on iPhone, start by going to Settings, then Phone
    2. Select Silence Unknown Callers, then slide the toggle to the right.

    On Android

    Android phones have a call feature that can help identify suspicious numbers and prevent unknown callers from disturbing you.

    Here’s how to block spam calls on Android:

    1. Open your phone app, then tap the three-dot menu > Settings > Caller ID and spam.

      The iPhone 'Phone' menu, with the Silence Unknown Callers option highlighted & the Silence Unknown Callers page on iPhone with the toggle switched on
    2. Toggle on See caller and spam ID and Filter spam calls.

    Protect your device against threats from spam

    With so much of our time spent online and so much data floating around, fraudsters, hackers, and scammers could find your phone number and other sensitive details. That’s why safeguarding your devices and maintaining your security is more critical than ever. Use AVG AntiVirus FREE to help protect your personal information and minimize the risk that it's used against you.

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    Michael Paulyn