What can someone do with your phone number, and what steps should you take if a scammer has it?

How can someone get your phone number?

Getting somebody’s phone number is not a matter of some high-tech hacking method, and it’s easier to do than you’d think. Your phone number can fall into the wrong hands in countless ways — some accidental, others deliberate. And in many cases, it’s the consequence of your behavior online. Here are the most common routes scammers use to get a phone number:

• Public exposure on social media. More often than not, it’s your own digital footprint that puts your phone number within a scammer’s reach. If you’ve listed your number on Facebook, Instagram, or LinkedIn, bots or identity thieves browsing social media networks can easily harvest it, especially if you haven’t properly configured your account’s privacy settings.
• Data breach. Hackers might steal massive amounts of personally identifiable information from online retailers, mobile carriers, or financial institutions. If you've used your number to register for any of these services, it might end up on stolen datasets at any time.
• Data broker lists and people search sites. Data broker companies compile your personal data from online and offline sources with the goal of selling it to marketers, and they do so completely legally. However, just because it’s legal doesn’t mean it can’t be dangerous. Cybercriminals can access that same data, including your phone number and other sensitive details, just as easily.
• Online forms, surveys, and giveaways. You may be asked to provide your telephone number when you enter contests, sign up for promos, or fill out online surveys. While usually it’s only a way for the company to contact you, these forms often bury consent in the fine print, which allows the marketing companies that created these documents to share your data. Sometimes these tempting offers may be a scam from the get-go.
• Stolen mail. While it may seem unlikely, criminals can gather your number from stolen mail, especially that containing bank statements or medical records.
• Social circle. It’s not always hackers or strangers, but people you know who are responsible for your information getting into the wrong hands. Someone in your circle, like your friends, coworkers, or even your employer, could unknowingly provide your number to an untrustworthy source.
• Phishing attacks. Fraudulent texts and emails might trick you into entering your phone number into phishing websites mimicking official services.

What can someone do with your phone number?

It might seem like your phone number is only a point of contact, but these days, it acts as so much more. With just your phone number, cybercriminals can launch a full-fledged attack on your identity, finances, and reputation. Here's how they do it.

Gather more information for identity theft

Your number is often linked to multiple parts of your online identity — social media, bank account, or paid subscriptions. While they can’t fully steal your identity using just your number, once a cybercriminal has your number, they can use it to gather other personal details like your full name, address, or even Social Security number through online searches in data broker sites and social media, data breaches, or social engineering. They may pose as you to trick customer service agents, reset account credentials, or apply for services in your name. 

Identity theft doesn’t always happen in one dramatic swoop. It can be a slow, methodical process that starts with a detail as basic as just your phone number. Once scammers piece together enough information, they can open new credit lines, intercept your email, or impersonate you in financial and legal transactions. 

Recovering from identity theft is time-consuming and stressful, often requiring months of effort to undo the damage. That's why it's crucial to protect even seemingly harmless personal details like your phone number.

Perform a SIM swap

SIM swapping is a type of scam where attackers take control of your phone number by tricking your phone provider into transferring it to a new SIM card they own. With your number in hand, they can intercept all your texts and calls. Controlling your number could potentially allow cybercriminals to break into your social media, email, crypto, or bank account.

Most people don’t realize what’s happening until it’s too late. Fixing the damage can be a long and stressful process, often involving police reports and hours on the phone with your mobile carrier. These attacks are becoming more common, and while carriers require verification, attackers may gather enough personal details through phishing or a data breach to convince support staff. That’s why it’s important to add a PIN or password to your mobile account and think twice before sharing your number.

Dox you

Doxing (also spelled “doxxing”) is the act of researching and publishing private data about someone online with the goal of harassing, intimidating, or threatening them. Your phone number can be a part of it — and often, the starting piece of the puzzle.

With only that one piece of data, a doxer can use it to look up other accounts and find more about you, including your home address, employer, names of family members, and social media profiles. They might post this information online or send it directly to your contacts. Even if it starts as an alleged prank, doxing can lead to real-world problems like stalking, harassment, job loss, or even threats of physical harm. 

And it’s not even limited to celebrities or public figures — anyone with a digital footprint can become a target. Once your phone number is out there, it can land on lists circulating among scammers or trolls, leading to nonstop calls or text messages. To protect yourself, keep your number off public websites and social profiles. If possible, use a second number for non-essential services. A little caution goes a long way.

Bypass 2FA

Two-factor authentication (2FA) is supposed to add more security to your accounts by asking for a second-step verification, usually through a code sent to your phone. But if a scammer gets hold of your phone number, they can SIM swap it and get these codes instead.

This type of scam is still so effective because many services still use SMS for identity verification today. Once a scammer takes over your number, they might break into your accounts, change your passwords, and lock you out. 

A far safer choice is to use app-based authenticators, which don’t rely on your number at all, or even hardware-based ones for especially most sensitive accounts, like your bank account.

Scam you

It’s rare, but scammers can use your phone number to pull off social engineering scams on you to trick you into giving up personal or financial information. 

One common tactic is pretending to be your bank, a delivery service, or a technical support representative. They’ll call or text using a fake number that looks real and say a problem occurred with your account. The message or call might sound urgent, asking you to “verify” your account, click a link, or share a code. Then they’ll ask you to “confirm” details like passwords or security codes. If you do, they can gain access to your accounts or even your money.

These scams use a sense of urgency and exploit your trust in these organizations. If anything appears suspicious, take a moment, drop the call, and contact the company directly using the official number you find on its website. Don’t click on any links or share any details. A few seconds of caution can save you a lot of trouble.

Blackmail you

If a scammer has your phone number, they might use it to dig deeper into your online activity and then use it to threaten or blackmail you. For example, they might claim to have hacked your device or possess compromising material on you and try to scare you into paying them to stay quiet. Some of these threats are completely fake, while others might use real information they’ve found online.

Even if they don’t have real evidence of compromising material, the fear of exposure alone can scare victims into paying. Some scammers send mass messages hoping to scare someone into responding. Other times, the blackmail is more targeted, using your phone number to connect with your email address or social profiles, then crafting believable threats. 

Either way, the goal is to make you panic and pay. Do not engage with such messages or comply with their demands. If someone tries to blackmail you, don’t reply or send money. Report the message and block the number. These scare tactics rely on fear, so staying calm and taking action is your best defense.

Send spam calls and messages

At a minimum, your number could be added to spam databases. And once your number ends up on these lists, you may start getting endless robocalls, phone scams, or, in general, weird text messages. The messages may try to trick you into clicking malicious links, giving away personal information, or paying fake fees.

While it seems like a simple annoyance, it can open the gate to more serious scams. Even simply answering can mark your number as “active,” making you a bigger target. And in some cases, scammers might spoof your number and use it to bother other people, making it look like you’re the one spamming.

The best way to minimize spam calls is to keep your number as private as possible, use call-blocking tools, and avoid interactions with calls or texts you don’t recognize. Once your number is out there, it’s tough to pull back.

Signs that a scammer has your phone number

It won’t always be immediately obvious, but several red flags can suggest your number has been compromised. If a scammer manages to gain access to your phone number, you may notice:

• A spike in spam calls or texts. If you receive an influx of scam calls or one-ring phone calls that hang up before you can answer, it could mean that your phone number has ended up on a spam list somewhere. One-ring phone scams try to get you to call back, often to a premium-rate number that charges hefty fees.
• Messages with verification codes or password reset attempts you didn’t ask for. Weird and random SMS messages with 2FA codes, verification links, or password reset prompts you didn’t request from your account can signal that somebody is attempting to log in to your account without your knowledge.
• Fake text messages pretending to come from legitimate sources. It can even be simple messages from senders you don’t know. These messages may contain phishing links, malware, or attempts to gather even more personal information.
• Unfamiliar numbers in your call or message logs. If you start seeing calls or texts from numbers you don’t recognize, especially if they’re frequent or come from unusual locations, it could be a sign that your phone number is compromised.
• Inability to make calls or texts. Sudden inability to send messages or make phone calls could mean someone performed a SIM swap on your card.

Should you be worried if a scammer has your mobile phone number?

If you think a scammer has gotten hold of your phone number, it's completely normal to feel concerned. However, your level of concern should really depend on what other information they have. Just your number may not be enough to fully impersonate you. However, if they get their hands on it, what someone can do with your Social Security number is far more serious — it can lead to full-on identity theft. Still, having your phone number leaked is definitely more dangerous than what someone can do with your email address.

That said, when your phone number is combined with details like your name, email address, or home address, it becomes a much bigger threat. With those few pieces, a scammer could try to bypass security questions, trick companies to gain access to your online accounts, or send convincing phishing messages. Knowing what to do if a scammer has your email address, number, or other personal information means changing your passwords right away, turning on two-factor authentication, and being cautious with unexpected calls, texts, or emails asking for more details.

If you'd like to learn more, you can take a look at our guide on what to do if a scammer has your email address.

What to do if a scammer has your phone number

If you suspect your number has been compromised, take immediate and decisive action:

• Block suspicious numbers on your device. Use your phone’s built-in features or third-party apps to block unwanted calls and texts. If you receive a call or message from an unknown or suspicious number, don’t hesitate to block it right away to prevent further contact. Regularly update your block list, since scammers often change numbers.
• Enable call filtering. Many smartphones now offer call filtering or detection services that automatically identify and block potential spam callers. You can also use carrier-provided tools or trusted apps that screen calls before they reach you. These filters won’t catch all scam calls, but they can reduce unwanted calls and protect your privacy.
• Monitor your online accounts for any unauthorized activity. Check your social media, email, bank, and other online accounts for signs of suspicious logins or changes. Set up alerts where possible to notify you of new sign-ins or password resets. 
• Change passwords for all online accounts linked to your phone number. If your phone number is connected to any online accounts, update those passwords immediately using strong, unique combinations of characters. Avoid reusing even strong passwords and consider using a reputable password manager to keep track of them. Doing so makes it much harder for scammers to gain access to your accounts using your phone number.
• Switch to app-based or biometric 2FA. SMS-based 2FA is vulnerable to SIM card swaps and interception, so using authentication apps or biometrics adds a stronger layer of security. App-based authenticators generate codes directly on your device without relying on your phone number. Options using your biometric data, like fingerprint or face recognition, are much harder to bypass.
• Alert your mobile service provider. Contact your phone provider immediately if you suspect your number has been compromised or you notice unusual activity. Request to add a PIN or password to your account immediately to prevent unauthorized changes, and consider asking that your SIM card be locked to block SIM swap scam attempts. In extreme cases, you might want to change your phone number altogether to cut off scammers.

How to protect your phone number

Prevention is your strongest defense. Here’s how to reduce the risk of your number falling into the wrong hands:

• Don’t post your mobile number on public platforms or social media accounts.
• Avoid using your phone number for giveaways or contest entries, or use virtual numbers for these needs.
• Enable a PIN for your SIM card and ask your mobile carrier to add account-level security measures.
• Refuse to provide your phone number at stores or events unless it’s strictly necessary.
• Never click on suspicious links from unknown senders.
• Don’t respond to suspicious messages or calls, because doing so can result in your being added to a spam call list.
• Avoid giving out your number during public Wi-Fi log ins.
• Check which apps have access to your device, SIM information, or personal identifiers and revoke any unnecessary permissions that could indirectly expose your mobile number.
• Shred physical mail that contains your phone number before discarding it.
• Get help from identity protection services to assist if your identity has been stolen.

NordProtect solutions to keep your identity safer

NordProtect’s identity theft protection service provides an all-around defense system to not only protect your personal details, like your phone number, but also your entire identity:

• The dark web monitoring feature alerts you if your cell phone number or other sensitive data is found on dark web forums.
• The credit monitoring feature informs you if anyone attempts to use your identity to open a new account or loan.
• The identity theft recovery feature offers expert assistance to help you recover from identity theft.
• The cyber extortion protection feature provides legal and technical support in handling cyber extortion schemes.
• The online fraud coverage feature helps reimburse you for financial losses from scams like impersonation, fake job offers, and crypto fraud.
• The cyber attack coverage feature offers support and reimbursement if malware, trojans, or ransomware compromises your devices or systems.

These NordProtect features are just some of those designed to help keep your identity safer and support you in the event of a threat.