Last updated: September 1, 2026
Changing your phone number abroad is one of those small admin jobs that quietly breaks fifteen other things. Your number stopped being a number years ago. It is now the key to your bank, your Apple Account, your WhatsApp history, your two-factor codes, and in some countries a large part of your legal identity. Change it without a plan and you find out which of those you can no longer get into — usually at the worst possible moment, in a country where the support line is closed.
I have done this move between Sweden, Colombia and Spain. And for seven years I ran a hotel in Colombia, where I watched the same problem arrive from the other direction: guests who could not approve a card payment because the code was going to a SIM sitting in a drawer at home.
Key Takeaways
- Your old number does not go quiet when you stop using it. Carriers recycle numbers and hand them to a new customer, in some cases after only three months — and every account still pointing at it now points at a stranger.
- The accounts that break hardest are the ones you cannot fix from abroad: banks, national eID, and anything that verifies you by calling the number you no longer have.
- There is a correct order to do this in. Almost all of it has to happen while the old number still works, which is the part most people find out too late.
What Happens to Your Old Phone Number After You Change It?
Your old number does not sit empty waiting for you. Once the line closes or a prepaid SIM goes dormant, the carrier returns the number to a pool and reissues it to a new customer. Depending on the provider, that can happen after three months. Every account still pointing at that number is now pointing at someone else’s phone.
The waiting period is a commercial decision, not a regulated one, and it varies enormously. A Which? investigation published in October 2024 asked 16 UK mobile providers how long they hold a disconnected number before reallocating it. The answers ranged from three months at the shortest to a year or more at the longest, with Three saying it holds numbers for at least 18 months. Same country, same regulator, a six-fold difference in how long you have.
Two things trigger this, and only one of them is a decision you make:
- You cancel the line. You move country, you stop paying for a contract you are not using, the number goes back in the pool.
- You stop using it. This is the one that catches travellers. Prepaid lines are usually deactivated after a period with no outgoing activity — no calls, no texts, no top-up. Incoming SMS does not always count. You can be abroad for four months, receiving codes perfectly well the whole time, and still lose the number because you never sent anything from it.
The second one is worth sitting with for a second. Nobody emails you to say your number is about to be recycled. The first signal is usually that a code stops arriving.
Which Accounts Break When Your Number Changes?
Not all of them break the same way. Some let you swap the number in thirty seconds from the app. Some require you to prove who you are with documents. And a few require you to be physically present in a country you have just left. That last group is the one to handle first.
| Account | What the number does there | Changing it from abroad | If the number is already gone |
|---|---|---|---|
| Your bank | Transaction approval and login codes | Varies wildly. Some banks do it in-app. Others require a call from the registered number, a branch visit, or a signed letter. | International support line and an identity check. Budget days, not minutes. |
| Apple Account | Trusted number for two-factor | Yes, while you can still sign in — Settings, your name, Sign-In & Security. | Account recovery, which is deliberately slow and can take several days. |
| Recovery and two-step verification | Yes, from account settings on any signed-in device. | Backup codes, or another device already signed in. Otherwise recovery. | |
| It is your account identity | Yes — the built-in Change Number tool migrates your account, but works best while both numbers are reachable. | You can register the new number, but you are starting a new account rather than moving the old one. | |
| Revolut, Wise, fintech apps | Login and 2FA | Yes, in-app, with a code sent to the new number. | Support ticket plus ID documents to prove ownership. |
| Crypto exchanges | SMS two-factor | Yes, but expect a security hold. Binance disables withdrawals for 24 hours after you change the bound number. | Full identity verification, sometimes with a video check. |
| Uber, Bolt, delivery apps | Account login | Yes, code to the new number. | In practice, a new account — and you lose ride history and saved payment methods. |
| National eID and tax portals | Legal identity | Often not. These are usually tied to a number registered in person, in country. | Frequently an in-person visit. This is the one that ruins a plan. |
Read that table in one direction: everything in the third column is easy only while the old number still receives messages. The fourth column is what happens when it does not. The entire job is about staying in column three.
Why Is a Recycled Number Worse Than a Dead One?
A dead number is an inconvenience — codes stop arriving and you notice. A recycled number is a security problem, because codes keep arriving and you do not notice. They arrive on a stranger’s phone, and password resets for your accounts go with them.
This has been measured. Researchers Kevin Lee and Arvind Narayanan at Princeton sampled 259 phone numbers available to new customers at two US carriers in 2021. Of those, 215 were recycled numbers that had belonged to someone else. And 171 of the 259 were still tied to the previous owner’s accounts on popular websites in a way that would have allowed the new holder to take those accounts over. Nineteen of the numbers were still actively receiving security-sensitive calls and messages when the researchers looked.
Two thirds of available numbers, still wired into somebody’s life. Nobody in that study did anything wrong except change their phone number and not tell every service about it.
How Do You Change Your Number Without Getting Locked Out?
Do it in this order, and do all of it while the old number still receives SMS. The whole method rests on one rule: never let a number die before you have finished moving off it. If you have already lost it, skip to the last step and start with your bank.
1. Build the list before you touch anything
You do not remember every account tied to your number. Nobody does. Search your email inbox for verification code, security code, and one-time, and read the sender list. That is your real inventory, and it is always longer than the one you would have written from memory. Write it down and mark which ones send codes by SMS rather than through an app.
2. Move what you can to an authenticator app
Every account you move to an authenticator app is an account that never has to care about your phone number again. Codes are generated on the device itself, so they work on a plane, in a dead zone, and in a country you have not told anyone you are going to. Do this first, because it shortens the rest of the list.
3. Download the backup codes
Google, Apple, and most serious platforms offer one-time backup codes. They are the only thing that reliably gets you back in when both the number and the device are gone. Save them somewhere that is not the phone you are about to change — a password manager, or paper.
4. Do the bank first, before anything else on the SMS list
Banks are the slowest to fix and the most painful to live without. Some will not accept a foreign mobile number at all, which is a conversation you want to have while you still have a working home number to be called back on, not after. If your bank offers app-based approval instead of SMS, switch to it now — that is the fix that survives every future move. Our guide to using your banking app abroad covers what else tends to break.
5. Use WhatsApp’s Change Number tool, not a reinstall
WhatsApp has a built-in Change Number function that migrates your account, your groups and your chats to the new number. Deleting the app and registering fresh does not do that. Use the tool, and use it while the old number can still receive a code. Your group chats depend on this working more than you would like.
6. Expect security holds, and do not travel through them
Changing a number is exactly what an attacker would do, so platforms treat it with suspicion. Withdrawal freezes of 24 to 48 hours are normal on financial platforms. Do not schedule these changes for the day before you need to move money, and do not do them from an airport.
7. Keep the old number alive for one more month
Once you think you are done, keep the old line active for another thirty days and watch what still arrives on it. Something always does. A gym, an airline, an old broker account, the service that only sends a code once a year. That final month is cheap insurance, and it is the difference between finishing the job and finding out about it in eight months.
Why a Local SIM Abroad Is the Wrong Place to Keep Your Codes
Because you are going to throw it away. A local SIM is bought for one country and one stretch of time. If you register your accounts against it, then every time you move you repeat this entire process — and each repetition is another chance to leave something behind on a number that gets recycled.
This is the pattern I see most in people who travel long-term. Not one dramatic lockout, but a slow accumulation of accounts scattered across three or four numbers they no longer hold. A Thai SIM from 2024 with a marketplace login on it. A Colombian number that still owns a crypto account. Individually, none of it matters. Together it is a list of accounts you cannot recover, and a stranger holding the keys.
The fix is boring: separate the two jobs your phone is doing. Data is local and disposable. Identity should be permanent. Use a travel eSIM for data in whatever country you are in, and keep one number for verification that does not change when your address does.
That is the thinking behind StayVerified — a real UK mobile number that only receives SMS, installed as a second eSIM alongside your data plan, from €11.99 for a month. It receives your codes from anywhere in the world, and it does not care which country you are living in this year.
One honest limitation, because it matters and nobody says it out loud: a second number cannot receive codes that were sent to your old number. Nothing can. What it gives you is a permanent address to move those codes to — so that step 1 through step 7 above is something you do once, rather than every time you change country.
Should You Keep Your Home SIM Alive Instead?
Sometimes, yes. Keeping your home line active is the simplest option and it is the right answer for a two-week holiday. It gets expensive and fragile once you are gone for months, because the line has to keep being paid for and kept active, and prepaid lines can be deactivated for inactivity while you are away. Here is the honest comparison.
| Keep the home SIM active | Authenticator app | A dedicated verification number | |
|---|---|---|---|
| Best for | Trips up to a few weeks | Everything that supports it | Services that insist on SMS, and people who move often |
| Cost | Your home plan, plus roaming charges | Free | A fixed fee for the term |
| Survives a country move | Only while you keep paying | Yes | Yes |
| Risk of losing it | Inactivity deactivation, recycling | Losing the device without backups | Letting the term run out |
| Works for banks | Yes, it is the registered number | Only if your bank supports app approval | Only after you register it with the bank |
For most people the answer is a combination: an authenticator app wherever it is offered, because it is free and it is the strongest option, and a stable number for the stubborn services that will only send an SMS. If you are keeping the home SIM, the dual SIM setup lets you run it alongside local data without swapping anything.
Frequently Asked Questions
How long before my old phone number is given to someone else?
It depends entirely on the provider. A Which? survey of UK networks in 2024 found holding periods ranging from three months at the shortest to a year or more at the longest, with Three reporting at least 18 months. There is no regulated minimum, so assume the shortest figure applies to you unless your provider says otherwise.
Can I lose my number just by being abroad?
Yes, on prepaid lines. Most prepaid plans deactivate a number after a period with no outgoing activity, and receiving messages does not always reset that clock. If you are away for months and want to keep the number, send an outgoing text or make a short call from it periodically, and keep credit on it.
What should I change my number on first?
Your bank, then anything holding money, then your Apple Account and Google account, then messaging. Banks are first because they are the slowest to fix, most likely to need a phone call or a branch visit, and the most disruptive to live without while you sort it out.
Will my bank accept a foreign phone number?
Some will, some will not. Policies differ by bank and by country, and a few only send codes to numbers issued in their own market. Ask before you need it, and switch to app-based approval if your bank offers it, because that removes the phone number from the equation entirely.
What happens to WhatsApp when I change my number?
If you use the Change Number tool inside the app, your account, groups and chats move to the new number. If you simply put in a new SIM and reinstall, you start a fresh account instead. Do the migration while your old number can still receive a verification code.
Is an authenticator app better than SMS codes?
For security and for travel, yes. Codes are generated on your device, so they do not depend on a mobile network, a roaming agreement, or a number you still own. The catch is that plenty of banks and services still only offer SMS, which is why most travellers end up needing both.
Can I get my old number back after it has been recycled?
Once it has been reissued to another customer, no. Before that point, some providers will reactivate a recently disconnected number if you contact them quickly. Speed is the only lever you have, so call the provider the moment you realise, not after you have finished troubleshooting the accounts.
Do I need a second phone for a second number?
No. Any phone that supports eSIM can hold several profiles at once, so a verification number can sit alongside your data plan on the same handset. You pick which one is used for what in your phone settings, and both are reachable at the same time.
Related Reading
- Will My Banking App Work Abroad?
- The Dual SIM Trick: Keep Your Home Number and Get Local Data
- eSIM vs SIM Card for Travel: Which Should You Get?
- The WhatsApp Problem: Your Group Chat Will Not Work Without Data
Data belongs to the country you are in. Your identity should not. Keep one number for verification codes and stop redoing this every time you move.