Caller ID spoofing is a technique scammers use to disguise the real number from which they are calling. Instead of displaying their true phone number, they make it appear as though the call is coming from a local number, a trusted business, or even someone you know. This guide explains what’s actually happening and what you can do to reduce it.
Quick answer: What Is caller ID spoofing?
Caller ID spoofing is when a caller deliberately falsifies the phone number displayed on your device. Scammers commonly use this technique to:
- Increase the likelihood that victims answer the phone
- Impersonate trusted organizations
- Hide their true location
- Avoid call blocking systems
Spoofing itself is not always illegal. For example, businesses may legitimately display a central callback number instead of an employee’s direct line. However, spoofing is illegal in many countries when used to commit fraud or deception.
How to stop spoofed calls
All of these steps will help reduce the number of spoofed calls that you receive:
1. Don’t answer unknown numbers
This sounds obvious, but it’s genuinely the most effective protection. If you don’t pick up, the scam fails. Save numbers from your doctor, pharmacy, and regular contacts to your address book. Anything else — even a local-looking number — can safely go to voicemail. Scam callers occasionally leave voicemails, but more often don’t. In my experience, genuine callers will leave a message.
2. Use a spam-blocking app
Spam blockers work by cross-referencing incoming numbers against databases of reported scam numbers. Some also use pattern recognition to catch new numbers that haven’t been flagged yet.
Reliable options include:
- Robo Shield — provides call filtering, scam detection, and real-time caller identification
- Truecaller — large crowdsourced database; free tier is solid
- Nomorobo — won the FTC’s Robocall Challenge; also works on some landlines
- YouMail — plays an “out of service” tone designed to get your number removed from calling lists
- RoboKiller — answers and terminates calls on your behalf; strong on robocalls
These are available for both iOS and Android.
3. Check your carrier’s built-in tools
All three major US carriers now offer free network-level spam filtering:
- Verizon: Call Filter (free tier available)
- AT&T: ActiveArmor
- T-Mobile: Scam Shield
These work before calls reach your phone. If you’re on a smaller MVNO, you may not have access to the same tools. Check directly with your provider.
In the US and Canada, carriers are also required to implement STIR/SHAKEN, an authentication framework that attaches a verification certificate to calls. Calls that can’t be verified may be flagged or blocked automatically. It’s not a complete fix, but it has reduced some categories of spoofed calls.
4. Register with your national Do Not Call list
This is worth doing, but set realistic expectations. Most serious phone scammers operate internationally and aren’t deterred by domestic registries. It’s more useful for reducing legitimate (but unwanted) telemarketing.
| Country | Registry |
|---|---|
| United States | Telephone Preference Service |
| United Kingdom | Telephone Preference Service |
| Canada | National Do Not Call List |
| Australia | Do Not Call Register |
5. Change your number if necessary
If your current number has been heavily targeted — or if it’s being spoofed by scammers and you’re receiving angry callbacks — a new number is often the cleanest solution.
When requesting a new number, ask your carrier for one that hasn’t been recently recycled. Recycled numbers often carry residual spam traffic from their previous owner. In the US, most major carriers will change your number for free. In Canada and the UK, some charge a small administrative fee.
6. Limit how widely your number circulates
Scammers source numbers from data brokers, public directories (such as Whitepages or 411.com), and purchased breach data. Reducing your exposure won’t eliminate the problem, but it can help over time.
Practical steps:
- Avoid entering your number into competitions or optional sign-up forms
- Uncheck any consent boxes that mention sharing data with third parties
- Use a secondary number (Google Voice provides a free number for US users) for online sign-ups.
- Get your number removed from people search sites such as Checkpeople and Nuwber. Automated removal services are available.
An ongoing problem
It’s worth being direct about limitations:
- Do Not Call registries have a minimal effect on overseas scammers
- STIR/SHAKEN helps but doesn’t block all spoofed calls — international calls often bypass it
- Spam apps rely on reported numbers, so brand-new spoofed numbers may get through before they’re flagged
- Changing your number is a reset, not a permanent fix — new numbers eventually get scraped too
The most reliable protection remains a combination of not answering unknown calls and using a carrier or app with active filtering.
If your number is being spoofed
If you’re receiving confused or angry calls from people you’ve never contacted, your number may be being used for spoofed caller ID. This is particularly disruptive and warrants quick action.
What to do:
- Contact your carrier immediately — they can sometimes flag or reassign the number
- Consider changing your number sooner rather than later
- Report the activity to the relevant authority for your country (see below)
You’re not liable for calls made using your number without your knowledge, but getting ahead of it reduces ongoing disruption.
How to report spoofing scams
| Country | Where to report |
|---|---|
| US | FCC complaint portal; FTC's ReportFraud.ftc.gov |
| UK | Report Fraud (0300 123 2040) |
| Canada | RCMP Fraud Reporting System; CRTC complaint form |
| Australia | Scamwatch; ReportCyber |
Common caller ID spoofing scams
Here’s some of the most common caller ID spoofing scams:
Neighbor spoofing
This is one of the most common spoofing tactics. Attackers spoof a number that closely resembles your own, often sharing:
- Your area code
- Your local exchange
- Similar digits
The goal is to create the impression that the call is local.
Government impersonation scams
Scammers pretend to represent:
- Tax authorities
- Immigration agencies
- Police departments
- Courts
Victims are pressured into making urgent payments or disclosing sensitive information.
Bank and Payment Fraud
Attackers spoof banks or payment providers and claim:
- Your account is compromised
- Fraudulent activity was detected
- Verification is required immediately
Victims may then be tricked into revealing banking credentials, one-time passcodes, and card information.
Tech Support Scams
Scammers impersonate:
- Companies such as Microsoft
- Internet providers
- Antivirus vendors
They claim your device is infected and attempt to gain remote access or payment.
Summary
Cheap VoIP services and large stolen data sets allow criminals to launch convincing robocall campaigns on an enormous scale. However, with network-level filtering, spam apps, and sensible habits around answering calls, most people can significantly reduce the extent to which they are affected. If your current number has become unmanageable, changing it is a reasonable and often underused option.
Thank you.
I keep getting constant phone calls from the same area code as mine over and over again. Even after I block those numbers I still get notifications of voicemails…but they are always blank voicemails…meaning no one leaving a message.
If the phone companies really wanted to stop this they could…They are making millions of dollars from scammers making thousands of phone calls to people a month…
The only way to stop this is for Congress to pass laws. They won’t because they personally make money on it. I would gladly give up receiving spoofed calls from my doctor once in a blue moon, to eliminate all of the hundreds of annoying calls I get a year that go unanswered but keep trying other numbers.
No, this is a product of greed from government and won’t stop until we end users wake up and smell the politics.
My view is this, if it is truly important, they will leave a voice mail and identify themselves very clearly as to who is calling so let it go to voicemail. If it is life and death important, they will send someone to your door such as the police. If you don’t have it set up, then make sure to set it up if you are an adult as this will be your valuable tool to get it right. It takes some time but when you never call back to these scammers then the game is not fun anymore, so they move on to someone else. With VOIP it is now worse but even at that it becomes boring to always call someone who does not answer. Eventually they will set up something to help us to stop it but until then just hang in there.
It is, it’s fraudulent – but you need to catch them first!
Our business line is being spoofed. Someone keeps calling us says we called him. After reviewing our records from our phone service carrier logs, we have never made any calls to the number that is calling us. So far he has called us twice and once told us to stop calling him. Our provider says there is nothing we can do. After owning our number for over 45 years, we aren’t going to change it now. At this point we can only tell the person to block our number if they call again. We have his number and name but do NOT intend to call him ever. How can this spoofing be stopped?
Within a week I received 20 calls incuding 11 yesterday and 7 so far today all from numbers in my area code. I don’t answer unknowns; they go to voicemail which tells them I’m on DNC list and if they are legitimate to leave a message. After spending almost 2 hours w/my provider – took 2 calls w/no option except to change my number which I won’t, a search turned up this site which quickly explained the problem. Sad part is these are legitimate numbers and innocent people are having their numbers hacked. As soon as I figure out which government official or office to send a report I will do so. I plan to give them the list of hacked numbers. If we all act, sooner or later they will do something!
I guess blocking these numbers is futile. They just keep making or taking on new ones. To use someone else’s phone number or create a phone number with a familiar area code should be illegal. Really!
The biggest problem with these spoofed numbers comes when the recipient MUST be able to receive calls from people outside their contacts. I work as a handyman, and 100% of new customers come from referrals. I do not advertise my service since I get more than enough work without doing so. That means I MUST answer calls from people who are not in my contacts, or eventually I will not have enough work to sustain the business. Every single time I get a call, I get anxiety about the possibility that the caller will just hang up, which means a scammer just verified that my line is active, and will sell that information to a gazillion other scammers. I will then receive an even greater volume of fraudulent calls. Currently, 95% of ALL calls I receive are scammers and robots. Its fricking insane, and ITS GOT TO STOP!
To add to the BS, these scammers have recently started spoofing the numbers of official city departments such as law enforcement and such. How is anybody ever supposed to have any confidence in anything they do over the phone these days!?
Setup voicemail mentioning you are attending to a job and will return the call as soon as possible. Scammers as a general rule don’t like voicemail.
I will NEVER answer the phone unless I recognize the full number. Every caller gets a voicemail message saying “Sorry, but I never answer calls because of scammers. Leave a message and number and I’ll get right back to you if you’re legit.” Scamming won’t stop – we just have to deal with it and not get mad. Life’s too short!
Dustin, my comment is not published yet, but I also need to receive calls at times from people I don’t know. I’ve set my phone to go to voicemail for unknowns and legitimate callers will leave a message. My message says, “this phone is silenced for unknown callers and on the do not call list, so if you’re a telemarketer or scammer, take it off your list. If you are calling for (name) or to inquire about (business) please leave your name & number and I’ll return your call asap.” You could reword to suit & still protect your business. It’s worked for me. The fakes never leave a message, but real people do.
Thanks for this tip that actually works!
I truly do not understand why scammers can have the ability to mask their true phone number!
It should be illegal to mask/spoof anyone’s true caller ID. Why does the software/app even exist?
I can’t think of ANY acceptable reason why anyone can have this ability to claim/pretend to be someone else – isn’t it illegal to impersonate another person?
I could not agree more. But most of the TCP/IP standards were written back when there was a trusted network in place and no reason to fake data because there was no way to monetize it. Security with TCP/IP and VOIP etc, were largely band-aids on these standards as it became problematic. This was a BIG mistake. Once standards are broken or abused, they are very hard to fix, because they are in such common use. Requiring caller verification right now would simply mean most valid calls would be rejected. Finally, caller validation means associating a person or legal entity with a device, a device with a sim, and a sim with a number. Go figure, most people who hate spam calls also hate government knowing who you are and where you are in terms of unique validated documents. Not much point knowing which company spammed you if it just leads to a dead drop post box and not a real person subjectable to a court of law. And all this has to be agreed internationally? A’int gonna happen, which is a shameful truth.