Phone Number Recycling and Old Accounts
When you stop using a phone number, networks eventually give it to someone else. Why accounts still linked to an old number are at risk, and how to update them before and after you change numbers.
Phone numbers are a limited resource, so networks recycle them. If you change numbers, move countries, or let a SIM lapse, your old number will eventually belong to someone else. Any account still using it for text codes or password resets is then partly in their hands.
Why it matters
- Password resets by text go to the new owner.
- Two-step codes go to the new owner.
- Messaging accounts tied to the number, such as WhatsApp, may be re-registered by the new owner.
- Banks and services may send alerts and information to the old number.
Most new owners are ordinary people who are simply confused by your messages. But a recycled number is also a way in for anyone who deliberately seeks one.
Before you give up a number
- List accounts that use it: email recovery, banking, mobile money, WhatsApp and other messaging, social media, shopping, government portals, work tools.
- Add your new number to each account, then remove the old one.
- Move two-step verification to an authenticator app or passkey where possible, so it no longer depends on any number. See text code weaknesses.
- Use WhatsApp's change number feature rather than just starting again.
- Tell your bank and update your number with any government services.
Moving abroad? Consider keeping your home number active at low cost until every account is updated. See moving countries: keeping access to your accounts.
If you already lost an old number
- Sign in to each account and replace the old number with your current one.
- If an account can only be recovered through the old number, use the provider's official account recovery process.
- Check recovery settings on your email first. See email recovery settings.
If you receive someone else's messages
If your new number receives codes or messages meant for someone else, do not use them. Ignore or delete them, and if a service keeps messaging you, tell it the number has changed hands.
Getting codes you did not request? Paste the message into CyberWatch AI Scan for a free check, and never share the code.
For more, read protecting your phone and number in our complete guide.
Frequently asked questions
What happens to my old number when I stop using it?
Networks usually recycle numbers after a period of inactivity and assign them to new customers. The new owner may then receive your old texts and codes.
Can the new owner get into my accounts?
Possibly, if an account still uses that number for text codes or password resets. That is why you should update your number everywhere before letting it go.
How do I find accounts linked to my old number?
Check your email, banking, mobile money, messaging and social accounts, your password manager, and any service that sends you text codes.
Sources
- How To Protect Your Phone From Hackers, US Federal Trade Commission
- Tips to complete account recovery steps, Google Account Help
- Recovering a hacked account, UK National Cyber Security Centre
