When you travel abroad, the SMS verification codes you normally take for granted can become harder to receive. Waiting for a code sent to your phone number—whether for logging in or confirming your identity—is one of the things that often trips people up overseas. This guide walks first-timers through how to prepare before you leave so you don't have to depend on SMS verification at all, by switching to an authenticator app (two-factor authentication app).
The Short Version
- Many services (Google, Apple, major social and cloud platforms, and more) let you switch from SMS to receiving codes through an authenticator app (TOTP). App-generated codes don't require a network connection, so they're far less affected by signal conditions while you're abroad.
- That said, some services—such as banks, brokerages, and credit card providers—are built around SMS or their own dedicated apps, and may not let you switch to an authenticator app. In those cases, you'll need a separate way to receive SMS messages on your home number.
- It's safest to get everything set up before you leave, while you can still receive codes on your phone number.
* This article reflects general information as of June 2026. Each service's options may change, so please check the official guidance from the relevant provider for the latest details.
Why SMS Verification Often Fails Abroad
SMS verification works by sending a code to your registered phone number. Abroad, that code can arrive slowly—or not at all—depending on your plan, your roaming settings, or local network congestion. This is especially true during long stays or study-abroad trips, where you may have suspended or cancelled your home number entirely and can no longer receive codes in the first place.
This is where an authenticator app (two-factor authentication app), which doesn't rely on SMS sent to a phone number, comes in handy. Switching over before you go can ease the worry of waiting for an SMS to arrive every time you log in while traveling.
What Is an Authenticator App (TOTP), and How Does It Differ from SMS?
An authenticator app generates a roughly six-digit code (a one-time password) on your phone that changes every set interval. Well-known examples include Google Authenticator and Microsoft Authenticator. Because generating the code itself doesn't use a network connection, the app can display a code even where signal is weak.
| Aspect | SMS Verification | Authenticator App (TOTP) |
|---|---|---|
| How you get the code | SMS sent to your phone number | Generated automatically in the app |
| Reliability abroad | Sensitive to network and plan conditions | Generated offline, so less affected |
| Keeping a phone number | Generally required | Often not required |
| Main thing to watch | Stops working if the number changes or is cancelled | Needs migration setup when you change devices |
The key point is that with an authenticator app, you can often have your verification code ready even without keeping an active phone number. On the other hand, it's important to store your backup codes in case you change phones or lose your device.
How to Switch Before You Leave
The screen names vary by service, but the overall flow is much the same. Try to handle this while you're still at home.
- List the services that matter: write out the accounts you're likely to log into while traveling—email, social media, cloud storage, shopping, and so on.
- Open each service's "Security" settings: look for the two-step or two-factor authentication option.
- Add your authenticator app: scan the QR code shown with your authenticator app, then enter the code it displays to complete registration.
- Save your backup codes: write them down on paper or store them in a password manager—keeping a copy somewhere other than your phone is the safest approach.
- Test it: log out once and confirm you can sign back in using the code from your authenticator app.
The first setup often takes just a few minutes, but it adds up when you have many services to cover. It's best to start with plenty of time to spare, not right before departure.
Some Services Can't Be Switched (Banks, Brokerages, Credit Cards)
Keep in mind that not every service supports authenticator apps. In particular, financial services such as banks, brokerages, and credit card providers often rely on SMS or their own dedicated apps for identity verification, and may not let you switch to an authenticator app. In those cases, you'll need a separate way to receive SMS on your home number while abroad.
If you plan to use financial services while traveling, also see our guide How to Receive SMS Verification from Home While Abroad: Preparing for Banks, Brokerages, and Credit Cards, which covers ways to receive SMS and how to prepare in advance. A practical approach is to mix and match: move what you can to an authenticator app, and cover the rest with an SMS solution.
What Bloomy's Data-Only eSIM Can and Can't Do
Many travelers use a data-only eSIM like Bloomy eSIM as their connection abroad. To set expectations: Bloomy plans are designed for data only. They include no phone number, no SMS, and no voice calls, so you can't use them to receive SMS sent to a phone number. That said, a data connection is genuinely useful in situations like these:
- Opening an authenticator app or a service's login screen (generating the code itself needs no connection, but the login process does require data)
- Receiving in-app notifications or push-style approval prompts (where the service supports them)
- Calls and messaging through apps like WhatsApp (available where a working data connection is present)
In other words, combining "set up identity verification with an authenticator app" with "cover your data with an eSIM" can take a lot of the stress out of logging in abroad. If you specifically need SMS to a phone number or voice calling, look into options beyond a data-only eSIM, such as a local SIM or a plan that includes a phone number.
Common Pitfalls and How to Handle Them
Plan ahead for changing or losing your phone
Because an authenticator app generates codes on the device itself, you can get locked out if you change phones or lose yours without preparing to migrate. Keep each service's backup codes, and check the migration and backup features within your authenticator app as well.
A clock that's off can reject your codes
Authenticator codes are based on the current time, so if your device's clock is significantly off, even a correct code can fail. Setting your phone's time to "automatic" is a safe bet.
Trying to switch everything at the last minute
When you have a lot of services, finishing them all before departure can be a lot of work. Starting with the highest-priority ones—finance, email, and the apps you use most—makes it easier to avoid gaps.
Want to Review Your Pre-Trip Prep in One Place?
The right connectivity for your destination depends on how much data you need, how many days you'll travel, and which countries and regions are supported. From the Bloomy eSIM comparison page, you can find a plan by country, data amount, and trip length. The plans and terms actually available can differ by country and region, so please check the latest details shown before you buy. If you get stuck on setup or usage, our FAQ can help, and you can browse phone-number and SMS topics in our phone number & SMS article list. Communication quality varies with the local network, your device, and your location.
Wrapping Up
The trick to not being at the mercy of SMS verification abroad is simple: before you leave, switch over whatever can be moved to an authenticator app. The less you depend on SMS sent to a phone number, the less you're affected by network conditions while traveling. Just remember that some services—banks, brokerages, credit cards—can't be switched, so cover those with an SMS solution and use each method where it fits. Handle your data with a data-only eSIM, and handle verification with a bit of preparation. That alone goes a long way toward easing the small anxieties around logging in abroad. Plan availability and pricing in USD can vary, so please confirm the latest details at the time of purchase. Note that Bloomy plans are subject to a fair usage policy.
