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7 min read
Published on July 15, 2024
Updated on September 4, 2025.
Most of us give out our phone numbers without much thought — whether to sign up for an online service, join a mailing list or connect with a new friend. However, your phone number can be more powerful than you realize, especially to a hacker. With it, hackers can send you phishing messages, impersonate you or even access your online accounts.
Continue reading to learn more about what hackers can do with your phone number, how they can get it in the first place and tips to keep it private.
What hackers can do with your phone number
While giving out your phone number may seem harmless, it’s sometimes all a hacker needs to access your private information and damage your devices. Here are some examples of what hackers can do with your phone number:
Target you with phishing attacks
Once hackers get your phone number, they can send text messages that appear to come from trustworthy sources, such as your bank or a delivery company. These phishing attacks use urgent language and include links designed to trick you into clicking and entering passwords, credit card numbers and other sensitive information. If you fall for phishing scams, you may end up sharing personal data that hackers can use to compromise your online accounts or even steal your identity.
Spam you with calls
Your phone number can be sold or shared on spam call lists, leading to an influx of robocalls, telemarketing scams and even threatening messages. These spam calls can be stressful and persistent, and they may trick you into sharing private information or making fraudulent payments. While some of these calls can be from legitimate telemarketers, they can also come from hackers with malicious intentions to steal your information or money.
Spoof your number
Phone number spoofing allows hackers to make it appear as if calls or text messages are coming from your number, even though they’re being made by someone else. This can harm your reputation if your phone number is used to harass others or carry out scams. You might also receive angry messages or calls from people, including your friends and family, who believe you contacted them.
Swap your SIM card to their phone
SIM swapping occurs when hackers convince your mobile carrier to transfer your phone number to a new SIM card that they control. They typically do this by impersonating you and claiming you lost your phone or had it stolen. Once your SIM card is swapped, hackers can intercept Two-Factor Authentication (2FA) codes, reset your passwords and even lock you out of your accounts.
Commit identity theft
Since your phone number is often connected to your digital footprint, hackers can piece together personal information like your full name, address or even Social Security number (SSN). They can find this kind of Personally Identifiable Information (PII) more easily if they combine it with information from a data breach or your social media activity. With this data, hackers can open fraudulent accounts or apply for loans in your name — potentially damaging your credit score and putting you in legal trouble.
Dox you
Doxxing occurs when someone posts your PII online, typically with the intent of harassing, threatening or embarrassing you. If a hacker has your phone number, they can use it to find other details and post them publicly. This can cause not only emotional distress but also real-world safety concerns.
How can a hacker get your phone number?
Hackers don’t always need advanced technology to find a phone number. Generally, they depend on publicly available information. Here are some of the most common ways hackers can get your phone number:
- Social media: Many people list their phone numbers on public social media profiles without thinking twice about it. Even if your number isn’t visible, it can be exposed through comments, group chats or platforms that share contact information.
- Data breaches: If you’ve signed up for an online service that has suffered a data breach, your phone number — along with other PII — may have been leaked. Data from these breaches is often sold on the dark web, making your number easily accessible to hackers.
- People search sites: Some websites, like Whitepages, collect personal information, including phone numbers, from public and semi-public sources to form expansive databases. Hackers can browse these people search sites to find phone numbers linked to names, email addresses or even home addresses.
- Public records: Depending on your location, certain public records, such as voter registration or property ownership, may include your phone number. These public records can be searched online or requested through official channels by anyone, including hackers.
- Online forms: When you sign up for a newsletter or online account, you’re often required to enter your phone number. While many platforms handle this information responsibly, some websites may sell your data to third parties, which is why you must read privacy policies thoroughly.
How to protect your phone number and your mobile device
Although it’s challenging to stay entirely anonymous online or be immune to all cyber threats, there are several steps you can take to protect your phone number and mobile device from hackers.
Secure your SIM card
To reduce the risk of SIM swapping, set up a PIN or password for your SIM card through your phone settings or by contacting your mobile carrier. Here’s how to set up a SIM lock on your iPhone or Android.
Important Disclaimer: When setting up a SIM lock, be careful not to enter the SIM PIN incorrectly three times. Doing so will stop your mobile service from working, meaning you’ll have to contact your mobile carrier to restore it.
How to set up a SIM lock on an iPhone
- Go to Settings
- Tap Cellular > SIM PIN
- Toggle the button next to SIM PIN to enable it
- Enter your mobile carrier’s default PIN, which is usually “1111” (double-check with your mobile carrier before entering this default PIN)
- Once it’s enabled, tap Change PIN
- Enter the default PIN again, then enter the new PIN you want to use to unlock your SIM card
How to set up a SIM lock on an Android
- Go to Settings
- Tap Security & Privacy > More security settings > SIM card lock
- Toggle the button next to Lock SIM card to enable it
- Enter your mobile carrier’s default PIN, which is usually “1111” (double-check with your mobile carrier before entering this default PIN)
- Once it’s enabled, tap Change SIM PIN
- Enter the default PIN again, then enter the new PIN you want to use to unlock your SIM card
Update your 2FA method to an authenticator app
SMS-based 2FA is better than no protection at all, but it’s more vulnerable to SIM swapping and interception. Instead of using SMS authentication, switch to an authenticator app like Google Authenticator, Microsoft Authenticator or Keeper for your online accounts. These apps generate codes on your device, so even if a hacker gets your phone number, they won’t have access to your 2FA codes to compromise your accounts.
Block spam calls
Blocking spam calls can help protect you from falling victim to scammers. While it’s nearly impossible to stop every unwanted call, there are several ways to block the majority of them and reduce your exposure to scams and phishing attempts:
- Contact your mobile carrier: Many mobile carriers offer free or paid spam-blocking services that detect and filter out spam numbers before they reach your phone. Check with your provider to see what options are available and how to enable them.
- Use a spam-filtering app: Apps like Truecaller and RoboShield are designed to identify and block spam calls in real time. These spam-filtering apps use large databases of reported spam numbers to prevent known scammers from reaching you.
- Sign up for the National Do Not Call Registry: Adding your phone number to the registry can reduce legitimate telemarketing calls. While it won’t stop all scammers, it will limit unwanted calls from legitimate companies.
Limit app permissions
Many apps request more access than they actually need, and some collect your phone number unnecessarily. To take more control over your number, review app permissions regularly in your device’s settings. If an app requests access to your contacts, microphone or SMS, deny it unless it’s essential. By limiting what apps can access, you minimize the chances of your phone number being exposed.
Protect your phone number against hackers
Hackers can use your phone number to access personal data, compromise online accounts and even steal your identity. Taking preventive measures like locking your SIM card, using an authenticator app and blocking spam calls can help you stay one step ahead of hackers.
Frequently asked questions
Can someone hack my phone with my number?
Yes, someone can hack your phone using just your phone number. With your phone number, hackers can launch phishing attacks, swap your SIM card or use your number to reset account passwords connected to SMS-based 2FA. Hackers can also spoof your phone number to impersonate you or gain access to your personal information. Although your phone number alone may not give them full access to your phone, it’s typically the first step in a larger attack.
What happens if you accidentally give a hacker your phone number?
If you accidentally give a hacker your phone number, you might become a target for scams and cyber attacks in the future. Hackers may start sending phishing text messages, also known as smishing, to trick you into clicking malicious links or sharing sensitive information. Your phone number may also be added to spam call lists or used in SIM swapping, which could lead to account takeovers. In some instances, hackers may use your phone number to collect more personal information through social engineering tactics.
