Your phone number is one of your most sensitive pieces of personal data

Most people share their phone number without a second thought — on signup forms, social media profiles, business cards, and online directories. But your phone number has become far more than a way to call you. It's a primary authentication factor for your bank accounts, a target for social engineering attacks, and a persistent identifier that ties together your entire digital life.

Once your phone number is exposed, the risks go well beyond annoying robocalls.

The real dangers of an exposed phone number

SIM swap attacks

A SIM swap occurs when an attacker convinces your mobile carrier to transfer your phone number to a SIM card they control. Once they have your number, they receive all your calls and text messages — including the two-factor authentication codes sent by your bank, email provider, and other services.

SIM swaps have been used to steal millions of dollars in cryptocurrency, drain bank accounts, and take over high-profile social media accounts. The FBI's Internet Crime Complaint Center reported over $68 million in SIM swap losses in a single year, and that figure only accounts for reported cases.

The attack typically starts with information the attacker already has: your name, address, date of birth, and the last four digits of your SSN — all of which are commonly found in data broker databases and breach data.

Smishing (SMS phishing)

Smishing is phishing delivered via text message. These attacks are increasingly sophisticated and effective because people tend to trust text messages more than email. Common smishing scenarios include:

Fake delivery notifications — "Your USPS package couldn't be delivered. Click here to reschedule."
Bank fraud alerts — "Suspicious activity detected on your account. Verify your identity at [malicious link]."
Tax scams — "Your tax refund of $3,247.00 is pending. Confirm your information."
Account verification — "Your [service] account has been locked. Click to verify."

These messages often create urgency and lead to convincing fake websites designed to steal your login credentials, financial information, or personal data.

Robocalls and voice phishing (vishing)

An exposed phone number will inevitably attract robocalls. While many are simply annoying, some are dangerous — sophisticated voice phishing operations that impersonate government agencies, tech support, or financial institutions. AI-generated voice technology has made these calls more convincing than ever.

Persistent tracking and profiling

Your phone number serves as a unique identifier across services. Advertisers, data brokers, and social media platforms use phone numbers to link your accounts and behavior across the internet. Even if you use different email addresses for different services, a shared phone number can tie them all together.

How your phone number gets exposed

Understanding the pathways helps you plug the leaks:

Data breaches

Major breaches have exposed billions of phone numbers. The 2021 Facebook breach alone exposed phone numbers for 533 million users. The 2024 National Public Data breach included phone numbers alongside SSNs and addresses for nearly 3 billion records.

Data broker listings

People-search sites like Spokeo, WhitePages, BeenVerified, and TruePeopleSearch aggregate phone numbers from public records, commercial databases, and user-contributed data. Your phone number is almost certainly listed on multiple sites alongside your name and address.

Social media profiles

Many people include their phone number in their social media profiles — sometimes publicly visible, sometimes nominally "private" but still accessible through the platform's search or contact-import features.

Online forms and signups

Every time you enter your phone number on a website — whether for account verification, checkout, or a loyalty program — it enters another database that could be breached, sold, or shared with third parties.

Public records

Voter registrations, property records, business filings, and court documents in many jurisdictions include phone numbers as part of the public record.

How to protect your phone number

1. Check your current exposure

Before you can fix the problem, you need to know how bad it is. Use PrivacyChecker's phone number scanner to see where your number appears in breach databases and data broker listings. Understanding your exposure is the essential first step.

2. Set up a SIM swap PIN with your carrier

Contact your mobile carrier and set up a port-out PIN or account security PIN. This adds a layer of protection that prevents an attacker from transferring your number without the PIN. All major US carriers now offer this:

T-Mobile — Account Takeover Protection in the T-Mobile app
AT&T — Extra Security passcode via your account settings
Verizon — Number Lock in the My Verizon app

This is one of the single most impactful things you can do. Set it up today.

3. Move away from SMS-based two-factor authentication

SMS-based 2FA is better than no 2FA, but it's vulnerable to SIM swaps. Wherever possible, switch to:

Authenticator apps — Google Authenticator, Authy, or Microsoft Authenticator generate time-based codes on your device
Hardware security keys — YubiKey or similar FIDO2 keys provide the strongest protection
Passkeys — The newest and most phishing-resistant authentication method, supported by an increasing number of services

Prioritize your most sensitive accounts: email, banking, and any accounts that could be used to reset passwords on other services.

4. Use a secondary number for online signups

Keep your real phone number private by using a secondary number for websites, forms, and services that require one:

Google Voice — Free, provides a separate number that forwards to your real phone
MySudo — Offers multiple virtual phone numbers with separate identities
Burner apps — Temporary numbers for one-time verifications

This creates a buffer between your real number and the inevitable breaches and data sharing.

5. Opt out of data brokers

Your phone number is listed on dozens of people-search sites. Removing it requires opting out of each one individually — a tedious but worthwhile process. Focus on the biggest sites first:

Spokeo, BeenVerified, WhitePages, TruePeopleSearch, FastPeopleSearch, Intelius

You can do this manually (expect to spend several hours) or use an automated removal service. See our guide to data broker opt-outs for detailed instructions.

6. Lock down your social media

Remove your phone number from the publicly visible sections of your social media profiles. On platforms where a phone number is required for account security, make sure it's set to "Only me" visibility. Also disable the "find me by phone number" feature — on Facebook, this is under Settings > Privacy > "Who can look you up using the phone number you provided?"

7. Be skeptical of every text message

Treat unsolicited text messages with the same suspicion you'd apply to unexpected emails:

Never click links in text messages from unknown senders
Never reply to messages asking you to verify account information
If a text claims to be from your bank or a delivery service, go directly to their website or app instead of clicking the link
Report smishing messages by forwarding them to 7726 (SPAM)

8. Register with the Do Not Call Registry

While it won't stop scammers, registering your number at donotcall.gov reduces legitimate telemarketing calls and makes it easier to identify illegitimate calls — if someone's calling to sell you something and you're on the list, it's more likely to be a scam.

Protecting your phone number is an ongoing process

New breaches happen constantly, and data brokers continuously re-collect information. A phone number you remove from one database today may reappear in six months. Regular monitoring and periodic opt-out sweeps are essential.

Check your phone number exposure now →