Guides · 5 min read
Bank codes not arriving abroad? Keep OTP working on a data only eSIM
Your travel eSIM has no phone number. That is what makes it cheap, and it is also why the code your bank just sent will never reach it. The bank texts the number on your account, which lives on your home SIM. If that SIM is switched off, pulled out, or has never registered on a network since you landed, the code goes nowhere and the payment fails.
This catches people out constantly, because the setup advice for a travel eSIM often says to turn off your home line. Do not. Here is the arrangement that keeps bank codes, WhatsApp verification and airline logins all working while the eSIM carries your data for a fraction of what roaming costs.
The setup: two lines, two jobs
Every phone that supports eSIM supports at least two active lines. Give each one a single job.
| Line | Job | Data roaming | Mobile data |
|---|---|---|---|
| Home SIM | Calls in, SMS in, bank codes | Off | Not selected |
| Travel eSIM | All internet | On | Selected |
With that arrangement the home line sits on a local network in receive only mode. Incoming texts are free on almost every major carrier. Incoming calls may cost you, so let unknown numbers ring out, but the calls still reach you, which matters if the bank's fraud team wants to talk.
iPhone
- Settings, Cellular. Tap your home SIM line. Data Roaming off. Leave Turn On This Line switched on.
- Tap the travel eSIM line. Data Roaming on.
- Back in Cellular, tap Cellular Data and choose the travel eSIM.
- Switch off Allow Cellular Data Switching, or the phone may quietly hop back to the home line and start roaming.
- Default Voice Line stays as your home SIM.
Android
- Settings, Connections, SIM manager (Samsung) or Network and internet, SIMs (Pixel).
- Set Mobile data to the travel eSIM. Set Calls and Messages to the home SIM.
- Open the home SIM and turn Data roaming off. Open the eSIM and turn Data roaming on.
Why the code still might not come
Even with both lines set up correctly, SMS while roaming is not guaranteed. It depends on your home carrier having a working roaming agreement with a network in the country you are in. Most do, for most countries. A few pairings are slow, and texts arrive in a batch twenty minutes late. And a small number of carriers, particularly budget prepaid brands that piggyback on a bigger network, do not include roaming at all unless you switch it on in their app before leaving.
So do a test before you fly. Send yourself a code from your bank, or trigger a WhatsApp verification, from the departure airport with the home line's data roaming already off. If it arrives on WiFi, you have proven the arrangement works.
Three backups for when SMS fails
1. The bank's own app approval
Most banks in the US, UK, EU and Australia now push a notification to their app and ask you to tap approve. That goes over data, which your eSIM handles fine. If you have never used it, log in at home and look for a setting called something like in app authentication, app approvals or push notifications for security. Turn it on. Many banks quietly prefer it and will stop sending SMS once it is enabled.
2. An authenticator app
Google Authenticator, Microsoft Authenticator, Authy or the bank's own generator produce codes on the phone with no network at all. They work at 35,000 feet. The catch is that almost every service requires you to enable them from a trusted, logged in session, which means doing it before you leave. Add your email provider and airline accounts while you are at it, because those also lock you out with SMS codes at the worst moment.
3. WiFi calling
If your home carrier supports WiFi calling, texts and calls route over any WiFi connection as if you were at home, no roaming agreement needed. Turn it on in Settings, Cellular, your home line, WiFi Calling. Some carriers will only let it work abroad if the phone connected to their home network recently, so enable it a few days out, not at the gate.
The five minute pre flight check: home line on with roaming off, eSIM on with roaming on and selected for data, WiFi calling on, bank app approvals on, an authenticator set up for email and the airline. Do this once and every future trip inherits it.
What about an eSIM with a phone number?
Some sellers offer plans with a local number and SMS. That is useful if you need to make local calls, book restaurants or receive a call from a hotel. It does nothing for bank codes, because the bank texts the number it already has for you, and it will not accept a temporary foreign number for security messages. Of the 236,811 plans we track, only 591 include voice and SMS at all, and they cost more than data only plans of the same size. Buy a number if you need to call. Do not buy one to fix two factor codes.
Removing the home SIM is the mistake
Older advice, from the days when travel meant a physical local SIM, was to swap your home SIM out and put it somewhere safe. With an eSIM there is no swap. The home SIM stays in, the eSIM sits next to it, and the only thing that changes is which one carries data. If you are handed a physical local SIM by a kiosk and your phone has a single slot, you now have the choice: local data, or bank codes. That is the strongest practical argument for an eSIM over a physical SIM, and it is the reason we only compare eSIMs on this site.
A last thing about the bank itself
Tell it you are travelling. Most banking apps have a travel notice under card settings. Without it, the first foreign transaction can trip the fraud filter, the card gets frozen, and the unfreeze flow wants, you guessed it, an SMS code. Set the notice, set up app approvals, keep the home line alive, and the eSIM does the rest.
Questions people ask
Can a data only eSIM receive SMS?
No. A data only plan has no phone number, so nothing can text it. Bank codes are sent to the number registered with the bank, which is your home SIM. Keep that line switched on, with data roaming off, and the codes arrive over the home network's roaming SMS, which is free or nearly free on most carriers.
Will my home carrier charge me for receiving SMS abroad?
Receiving texts abroad is free on almost every major carrier in the US, UK, EU, Canada and Australia. Sending them costs money. Data roaming is the expensive part, and that is why you turn data roaming off on the home line and let the travel eSIM carry the data.
What if my bank only sends codes by SMS and the text never comes?
Wait five minutes, then toggle airplane mode. If still nothing, check the home line is enabled and that it has registered on a network (you should see a carrier name next to it). If SMS is genuinely blocked while roaming, call the bank from the app or use their in app approval, most banks have one now.
Is an authenticator app safer than SMS for travel?
Yes, and more reliable. Google Authenticator, Microsoft Authenticator and the bank's own app generate codes on the phone with no network needed. Set them up at home, because most banks require you to be logged in on a trusted device to enable them.
Does WiFi calling deliver SMS abroad?
On many carriers, yes. If your home carrier supports WiFi calling and you are on WiFi, texts often come through even where the roaming SMS is flaky. Enable it before you leave. Some carriers require the phone to have connected to their network in the last few days for it to work abroad.
Should I buy an eSIM with a phone number instead?
Only if you need a local number for calls. A number on a travel eSIM does not fix bank codes, because the bank still texts the number it has on file for you. The reliable route is your own home number, kept alive.
Compare plans for the places in this guide
236,811 plans from 61 sellers, ranked by real price per GB, with prices checked against the shops themselves.
