- There are multiple free tools and apps to identify unknown number owners and block spam.
- Using search engines, directories, and home tricks can provide key information about the origin of a call.
- Operators and the law offer mechanisms to protect your privacy and report abuse or telephone harassment.
Have you received a call from an unknown number and want to know who it belongs to? These days, receiving calls from unknown numbers is commonplace and can be a nuisance or a cause for concern, especially given the proliferation of spam calls, telemarketing scams, and potential fraud attempts. However, discovering who's behind that number is now easier than ever thanks to numerous digital tools and resources.
In this comprehensive guide, we explain in detail how to identify the owner of an unknown phone number , from free search engines and apps to official registries and tips for protecting yourself against these types of calls. You'll learn how to use online resources, trusted apps, simple tricks, and best practices to avoid future problems.
Why do we receive calls from unknown numbers?
Unidentified calls are becoming increasingly common. The reasons can vary: from mass marketing campaigns and company notifications to errors, contacts not saved in your address book, and even attempts at deception or phone scams. It's important to distinguish between a blocked number (one the caller has configured to hide their identity) and an unknown number (a number visible but not saved in your contacts).
- Phone spam: Unsolicited commercial calls, surveys, sweepstakes and promotions.
- Telephone fraud or scams: Scammers are looking to obtain personal or banking information.
- Legitimate companies: Service calls, banks, insurance companies, deliveries, etc.
- Unstored contacts: An acquaintance, family member, or institution that you didn't save in your address book.
What to do when receiving a call from an unknown number?
Before answering a call, it is advisable to:
- Do not return the call immediately: First, try to find out the source to avoid falling for scams or premium rate calls.
- Do not share personal information: If you answer, do not provide confidential information.
- Block or report the number if you detect that it is spam, harassment or possible fraud.
- Use the identification tools which we detail below to know the identity of the owner.
Methods to identify the owner of an unknown phone number
There are several strategies for identifying the owner of a phone number . Some require the use of mobile apps, others online platforms, or official directories. Choosing the most suitable one depends on your needs and the type of number you want to identify (mobile, landline, national, international, anonymous).
- Query in Internet search engines
Type the number into Google, Bing, or any other search engine in international format (+34 for Spain, +52 for Mexico, etc.). Search engines may return results from forums, complaint sites, business directories, or social media sites where other users have reported the same number.- Advantages: Fast, free and without registration.
- Disadvantages: You don't always get results if the number is private or very recent.
- Use caller ID apps
There are several apps and services that allow you to identify the identity and reputation of a number based on massive collaborative databases. The most popular include:
TrueCaller
Truecaller is probably the most recognized caller ID app worldwide. It uses a database of numbers reported by both its global community and public records.
- Available on Android, iOS and web version.
- Automatically identifies calls and blocks spam and fraud.
- When searching for a number, you can see the name of the owner, whether it's spam, a business, a private individual, etc.
You must create an account using your mobile phone, email, or social media login. The privacy policy is transparent, but by using it you contribute your address book (anonymously) to improve the database.
tellows
Tellows stands out for its active international community. It allows users to search for unknown numbers, view reviews from other users, and rate calls as reliable or dangerous.
- Available for Android and iOS, as well as a web version.
- Allows you to report harassment, fraud, or identify companies.
- Includes maps and rankings of areas with the most reports of dangerous numbers.
Whoscall
Whoscall is a highly rated app for recognizing and blocking unwanted calls from both known and hidden phone numbers, with the ability to also identify suspicious SMS messages.
- Allows you to create your business card and automatically filter unwanted calls.
- Provides offline identification in many cases.
- Compatible with WhatsApp, Messenger and other messaging apps.
Hiya
Hiya is another highly rated alternative. Its main function is to block spam and provide real-time alerts about suspicious calls, as well as enabling reverse phone lookups.
- Extensive database of numbers reported internationally.
- Automatic and customizable call and message blocking.
- Includes premium features for advanced protection.
Other popular applications
- Calls Blacklist: blocks SMS and unknown calls.
- Mobile Number Locator: specialized in geographic location and backed by millions of downloads.
- CallApp: Caller ID with recording features and protection against WhatsApp spam.
- Showcaller: Identifies and blocks unwanted calls, with a database of more than 200 million records.
Homemade tricks to find out the owner of a number
- Save the number and check WhatsApp: Add the number to your address book and check if it has a photo or name on WhatsApp. Sometimes, the image or status can reveal the owner's identity.
- Search on social networks: Enter the number on Facebook, LinkedIn, Twitter, and Instagram. If the owner has linked it to an account, you may see additional details.
- Check on Google Maps: If you are a business, the number is often linked to your business listing.
Online directories and specialized websites
If the number isn't listed on any apps or social media, you can check out databases and websites specializing in collecting complaints and user experiences:
- SpamList: Free service for identifying and reporting spam calls, with millions of reported numbers and an easy-to-use reverse search.
- I tell you: Spanish forum where users identify numbers and leave comments about the origin of calls.
- WhoCalls: Spam phone database, allows you to search and report fraudulent or harassing campaigns.
- SpamPhone: Reverse phone book to discover the nature of a number, with options to read and leave reviews.
- Who Calls Me: Mainly in English, useful for searching international numbers with user reviews and alerts.
- PhoneNumbers.com: Available in Spain, Mexico, Argentina, Colombia, and Peru, it compiles reports and opinions on problematic numbers.
- Emobiletracker: Track mobile numbers globally, showing provider, country, and other useful details.
- Infobel: International business and personal directory, especially useful for landline and professional telephone numbers.
- Yellow Pages: Digital version of the classic business directory, useful for identifying companies.
Special codes and functions to track unknown calls
- Code *57: It allows you to track the last call received and notify the service provider, useful in cases of threats or harassment (check if it's available in your country and operator; it may incur a fee). Want to know more?
- Code *69: Especially in North America, it allows you to return the last call and hear the number that made it, although it may expose your number to potential spammers if you return the call.
- Prefixes to hide number: To call with a hidden number, in Spain and many other countries, you use #31# before the number. For landline-to-mobile calls, it's usually 067.
Identification via the Google Phone app and mobile settings
Modern mobile phones include built-in features to filter and alert you about potentially suspicious calls. If you'd like to learn more about these options, you can consult our article on how to identify a phone's carrier, which may also be useful in other contexts.
- Android: The Google Phone app identifies business calls and spam calls and allows you to set up blocking for unknown numbers. Activate detection in Settings > Caller ID and spam.
- iOS: Allows you to silence unknown numbers (Settings > Phone > Silence Unknown Calls) and block contacts. Some advanced features require third-party apps like Hiya or Truecaller.
Can you find out who is calling from a hidden or private number?
A hidden number is one that the caller configures to not display their identification during the call . The recipient will only see messages such as "hidden number," "private," or "unknown," without being able to identify the real number.
In these cases, there is no public and legal method to obtain the identity of the sender unless the judicial authorities intervene, who can request the call logs from the operators in cases of crime or serious harassment.
- Some tracking services and apps promise to unmask private numbers, but their reliability is very limited and they rarely work with truly hidden numbers.
- In cases of persistent threats, harassment, or fraud, gather evidence (recordings, messages, schedules) and report to the police.
How to avoid and block calls from unknown or spam numbers
- Manual lock: Both Android and iPhone allow you to add any number to your "blacklist" or block it from your call history.
- Filter unknown calls: Turn on the "Silence Unknown Calls" feature on iOS or block all calls from unknown numbers on Android using the Phone app options.
- Use blocking applications: TrueCaller, Hiya, and other apps offer automatic block lists for numbers reported as spam or fraud.
- Request blocking from your operator: Many carriers offer a service that restricts incoming calls from spam or hidden numbers; check for availability.
- Sign up for the Robinson List: A free registration where you can indicate that you do not wish to receive unsolicited marketing or calls from companies. Registration helps reduce the volume of spam, although it is not infallible against companies with which you already have a relationship.
Legal Protection and Privacy: What You Need to Know
- The General Telecommunications Law prohibits unauthorized commercial calls, with exceptions (due to an existing business relationship, for example).
- Reporting fraudulent or harassing calls helps improve databases and helps operators restrict or penalize spammers.
- Sign up for the Robinson List and update your privacy preferences with any company you partner with to minimize unwanted telemarketing.
Tips to keep your number protected and avoid unknown calls
- Avoid posting your number on social media, public forums, or websites.
- Do not include it in sweepstakes, surveys, or unnecessary registrations.
- Use messaging apps that allow you to limit who can see your number.
- Be wary of “free” forms and low-reputation applications.
- In case of doxing (exposing your number online), contact the appropriate authorities.
Frequently Asked Questions About Identifying Unknown Numbers
- How can I find out who owns a cell phone number? Use identification apps, Google searches, and online directories. If no information appears, save the number and check it on WhatsApp or social media.
- Are ID apps secure? The best-known ones (TrueCaller, Hiya, Whoscall) are reliable, but always check the permissions they request and their privacy policy.
- Can the identity of a private number be discovered? No, unless the authorities do so by court order and with the cooperation of the operator.
- How do I block unknown calls? From official calling apps on Android/iOS, through third-party apps, or by requesting the service from your carrier.
Today's technology makes it increasingly easier to identify and block unknown numbers, but the best defense is prevention, responsible use of your data, and awareness of the tools at your disposal. By applying the methods and tips explained in this guide, you'll be able to know who's calling you, when it's safe to answer, and how to protect your phone privacy against any attempted intrusion, harassment, or scam.
