Check if your phone number was leaked in a data breach
Type your number with its country code to see whether it is in breach records, how many, and what leaked alongside it.
- Free, five checks a day
- Masked results
- Nothing is sent to the number
Why phone numbers leak
A phone number is in more data than most people expect, and unlike a password it can’t easily be changed.
Sign-ups and deliveries
Shops, delivery apps, booking sites and loyalty schemes ask for a number, and their customer data is a common target.
Contact lists
Apps that upload a contact list hold the numbers of people who never used them, so a number can leak from a service its owner never signed up to.
Scraped profiles
Numbers attached to social profiles have been scraped and collected in bulk, then shared alongside names and profile links.
What a leaked number is used for
Scam texts and calls that know your name and the service you use, which makes them far more convincing than random spam.
SIM swapping: someone persuades your carrier to move your number to their SIM, then receives your text message codes and resets your accounts.
Account lookups: a number is often enough to find the accounts and profiles registered with it.
Protecting a leaked number
Lock the number with your carrier
Ask for a port-out PIN or number lock, so it can’t be moved to another SIM without it.
Move off text-message codes
Use an authenticator app or a passkey for email, banking and anything else that matters.
Distrust texts that know too much
A message using your name and a real company is not proof it is genuine. Contact the company yourself.
The full records are on Seer
This site shows how many breach records hold what you searched, and a masked sample of them. The check is run by Seer, which shows the full records: which breach each came from, when, and what leaked with it.
Seer also searches stealer logs, the records malware takes from infected devices, and finds the social accounts tied to an email address, username or phone number.
Try Seer’s free check- Breached credentialsEvery record an email address, username, phone number or domain appears in.
- Stealer logsLogins captured by malware on infected devices, searchable by email, username or domain.
- Social accountsAccounts on 740+ platforms by username, 106 by email address and 20 by phone number.
- Plans and pricingWhat a free account includes, and what the paid plans add.
Questions
How do I check if my phone number was leaked?
Type it with the country code, as in +1 555 555 0123, and search. Ten digits on their own are read as a US or Canadian number. The result shows how many breach records hold it.
What can someone do with a leaked phone number?
Send convincing scam texts and calls, try to take over accounts that reset by text message, or talk your carrier into moving the number to their SIM. Knowing it leaked tells you which of those to guard against.
How do I protect a leaked number?
Ask your carrier for a port-out PIN or number lock, move important accounts from text-message codes to an authenticator app or a passkey, and treat unexpected texts that know your name with suspicion.
Why did my number turn up in a breach I never signed up for?
Numbers leak from apps that uploaded a contact list, from delivery and booking services, and from data scraped off public profiles. You don’t have to have used a service for your number to be in its data.