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WiFi Calling eSIM: How to Receive Verification Codes Anywhere

You're at Barcelona airport, ready to book your Uber to the hotel. The app asks for an SMS verification code. You wait. And wait. Nothing arrives.

How verification codes actually work with SIM, eSIM, and Wi‑Fi Calling

You're at Barcelona airport, ready to book your Uber to the hotel. The app asks for an SMS verification code. You wait. And wait. Nothing arrives.

Your phone shows full signal—your new eSIM is working perfectly for Google Maps, WhatsApp, everything else. But that critical text message? It never comes. Now you can't access your bank account, your email, or any app that needs 2FA. You're effectively locked out of your digital life the moment you need it most.

Sound familiar? This "eSIM + Wi-Fi Calling + verification code blackhole" problem hits thousands of travelers every day. The frustrating part? Your phone isn't broken. Your eSIM isn't faulty. It's usually just a settings mismatch that takes 5-10 minutes to fix once you know what to look for.

In this guide, we'll walk you through exactly why this happens and how to fix it—whether you're dealing with a data-only travel eSIM, a newly transferred eSIM from your carrier, or just trying to understand why codes stopped arriving the moment you enabled Wi-Fi Calling.

How verification codes actually work with SIM, eSIM, and Wi‑Fi Calling

A full voice/SMS eSIM (SIM điện tử tích hợp sẵn trong điện thoại) can receive verification codes just like a physical SIM, as long as the plan includes SMS and your carrier has set it up correctly. If your carrier supports SMS over Wi‑Fi Calling, those codes can even arrive when you only have Wi‑Fi. But data‑only travel eSIMs cannot receive verification texts at all because they don’t include a phone number for SMS.

Here’s the simple path a verification code usually takes:

The app or website (bank, email, social network) asks to send a code.
It sends a request to your carrier using the phone number on your account.
The carrier routes the message into its SMS/short code system.
The SMS is delivered to your line (physical SIM or eSIM) as:
- Regular SMS over cellular, or
- SMS over Wi‑Fi Calling, if your carrier supports it and Wi‑Fi Calling is active.
Your phone receives the code in the default messaging app.

A few key distinctions:

Physical SIM vs eSIM:
If both are on the same phone number and plan, they behave the same for SMS and verification codes. The “electronic vs plastic” part doesn’t matter; the phone number and carrier plan do.
Data‑only eSIM vs voice/SMS eSIM:
- Data‑only eSIM: Internet only, no phone number, no SMS, no verification codes.
- Voice/SMS eSIM: Has a real mobile number, can receive SMS and verification codes if the plan allows it.
Cellular SMS vs SMS over Wi‑Fi Calling:
- Some carriers deliver verification codes over cellular only.
- Others support SMS over Wi‑Fi Calling, so codes can come through even with no cellular signal, as long as Wi‑Fi Calling is active on that line.

Short code verification texts vs regular SMS

Most verification codes come from short codes, not from normal phone numbers.

Why this matters:

Carriers can block short codes or “premium SMS” separately from regular person‑to‑person texts.
You can be in a situation where:
- Messages from friends arrive normally,
- But all OTP/verification texts from short codes never show up, because of account settings or spam filtering on the carrier side.

This is a big reason you might think “SMS is working,” yet every login code fails. It’s not your phone being cursed; it’s often how your carrier treats short codes on your line, especially after changes like moving to an eSIM or switching phones.

Common scenarios where eSIM + Wi‑Fi Calling break verification codes

In real trips, problems usually fall into a few patterns. Spotting which one you’re in will save you a ton of time.

You land in Paris, install a travel eSIM, turn off your home SIM to “avoid roaming,” and suddenly none of your bank codes arrive. Or you move your number from a physical SIM to an eSIM on a new iPhone, and from that moment, OTP texts just vanish.

Here are the usual suspects.

Data‑only travel eSIM is active, home SIM is off

The Setup: You're using a data-only travel eSIM to get cheap internet abroad. To avoid roaming charges, you've turned OFF your home SIM/eSIM completely.

The Problem: When your bank sends a verification code, it goes to your home phone number—the one on your home SIM back in your home country. Since that SIM is turned off, the message has nowhere to go.

Why Travel eSIM Can't Help: Your travel eSIM has no phone number at all. It's data-only (internet access), so it can't receive SMS texts or verification codes even if the app tried to send them there.

Example: You’re in Rome with a data‑only eSIM for maps and social media, but your bank sends an OTP to your US or UK number on the home SIM you turned off. The SMS has nowhere to go.
Recently moved your number from physical SIM to eSIM

What Happened: You recently upgraded phones or converted your old physical SIM card into an eSIM. Regular calls work fine, but verification texts mysteriously stopped arriving.

The Hidden Issue: Your carrier's system hasn't fully updated to recognize your new eSIM for all message types. Specifically:
- Regular SMS from friends goes through (person-to-person texts)
- But verification codes from short codes (like 12345) get blocked
- The carrier's system still thinks your old SIM should receive these special messages
Technical Term: This is called incomplete "provisioning"—think of it like your eSIM got 80% set up, but the verification code routing didn't get turned on yet.
- Example: After moving to an eSIM on a new iPhone, you can text friends but stop getting 2FA codes from your bank and Apple ID.
Dual SIM / dual eSIM; wrong default SMS line
Modern phones often run two lines at once (dual SIM or dual eSIM).
- Your phone may be trying to use the wrong line as the default for SMS.
- Apps might send verification requests tied to one number, while your default SMS line is another.
  Example: You have a US line and a local EU line; the bank has your US number, but your phone’s default SMS line is set to the EU eSIM, so things get weird and messages don’t show up where you expect.
Codes only fail when on Wi‑Fi; work on cellular
On Wi‑Fi at your hotel, no codes arrive. As soon as you step outside and switch to cellular, codes show up.
- Your carrier may not support SMS over Wi‑Fi Calling, or only supports it in your home country.
- Wi‑Fi Calling might not actually be active (no icon next to the signal bars), so SMS must go over cellular—which you don’t have when you’re deep indoors.
  Example: In your Airbnb abroad, you’re on Wi‑Fi with a travel eSIM for data. Your home line has no cellular signal in the building and Wi‑Fi Calling isn’t active, so OTP texts don’t reach you until you walk outside and your home SIM briefly catches a roaming signal.

Quick self-check: which number is your code going to?

Before diving into deep troubleshooting, it helps to confirm you’re pointing everything at the right phone number.

Check the number inside the app/service.
In your bank or app’s security settings, confirm which phone number is registered (country code + last 2–3 digits). Make sure it matches the line you actually own and use.
Check which SIM/eSIM line is active on your phone.
On your device, see which line is turned ON and which one supports voice + SMS (not just data).
Set the correct default SMS line.
- If you have dual SIM/eSIM, set the line that matches the app’s phone number as the default for SMS.
- Alternatively, change the phone number in the app to match the line you actively use.
Re-request the code.
Once the number in the app and the active SMS line on your phone match, request a fresh verification code.

Step‑by‑step troubleshooting checklist (before calling your carrier)

Before sitting on hold with support, run through this checklist. It covers most “wifi calling esim receive verification codes” issues that you can fix yourself.

Basic connectivity & line checks

You want to confirm that the line which should receive codes is actually active and has a way to reach the network (cellular or Wi‑Fi Calling).

On iOS (iPhone):

Go to Settings → Cellular (or Mobile Data).
Make sure the line that should receive SMS is turned ON.
Tap Default Voice Line or Default Line, and ensure that line is selected for voice & SMS if that’s your main number.
Scroll to Wi‑Fi Calling:
- Turn it ON for that line if your carrier supports it.
- When connected to Wi‑Fi, check the status bar for a Wi‑Fi Calling indicator (often your carrier name + “Wi‑Fi” or a phone + Wi‑Fi icon).
Make sure Airplane Mode is OFF. If you need to save roaming, you can disable Data Roaming but keep the line itself active for SMS and Wi‑Fi Calling.

On Android (paths vary by brand, this is the general idea):

Go to Settings → Network & Internet → SIMs (or Connections → SIM manager).
Confirm your main line (the one with your bank/app number) is turned ON.
Set that line as the default for Calls and SMS.
Under Wi‑Fi Calling, enable it for that SIM/eSIM if your carrier supports it, and check for a Wi‑Fi Calling icon when on Wi‑Fi.
Ensure Airplane Mode is OFF and that you see at least some signal bars, or a Wi‑Fi Calling icon if you’re indoors.

If your phone shows no signal and no Wi‑Fi Calling for the line expecting the code, verification SMS simply has no route to you.

Check SMS settings, blocking, and spam filters

Sometimes codes are arriving but being filtered or blocked by your phone or apps.

Open your Messages app and check any Spam/Junk or Filtered folders.
Look at your Blocked contacts/numbers list and remove any odd short codes or unknown numbers that might have been accidentally blocked.
Temporarily disable third‑party SMS blocker apps or aggressive spam filters.
Ask a friend to send you a regular SMS:
- If you receive it and can reply, basic SMS is working.
- If you don’t receive it, there’s a deeper SMS issue on that line beyond just verification codes.

Try network & device refresh (safe steps)

These are light resets that often clear stuck routing or activation issues.

Toggle Wi‑Fi Calling:
- Turn Wi‑Fi Calling OFF, wait 10–20 seconds, request a verification code.
- Then turn Wi‑Fi Calling ON again, wait until the icon shows, and request another code.
Toggle the eSIM line:
- Turn your affected line OFF in SIM settings, wait 10–20 seconds, then turn it back ON.
Restart your phone:
- Power off fully, wait 30 seconds, turn it back on, then re‑request a code.
Reset Network Settings (last resort on your side):
- This clears cell, Wi‑Fi, and Bluetooth settings.
- Only do this if nothing else works and you’re comfortable re‑entering Wi‑Fi passwords.
- On iPhone: Settings → General → Transfer or Reset → Reset → Reset Network Settings.
- On Android: usually Settings → System → Reset options → Reset Wi‑Fi, mobile & Bluetooth.

Warning: Resetting network settings will erase saved Wi‑Fi networks and Bluetooth pairings. It won’t delete your data, but it is annoying to set up again, so keep it as a last step.

Test with a different verification service

This helps you figure out if the issue is with your carrier/eSIM or with a specific app.

Request an OTP SMS from another service that you use (for example, a different email provider, a messaging app, or a cloud service).
Compare results:
- If other services’ SMS codes arrive, your carrier and eSIM SMS are mostly fine; the problem likely lies with the original app or service.
- If no verification SMS from any service arrives, even though regular texts work, it’s more likely a carrier issue with short codes or provisioning.

When the problem is your carrier (short codes, premium SMS, eSIM provisioning)

If you’ve checked your lines, Wi‑Fi Calling, and basic SMS, but all verification codes still fail, the issue is often on the carrier side.

Typical signs it’s a carrier problem:

Regular SMS with friends work, but no short code OTP from any app arrives.
The problem started right after you:
- Switched your number from a physical SIM to an eSIM, or
- Swapped to a new phone with an eSIM transfer.
You’re abroad, on roaming or Wi‑Fi Calling, and have never tested codes since the change.

Common carrier‑side causes:

Short code or premium SMS blocked on your account for security or billing reasons.
Your line is not fully provisioned for SMS or short code messages on the new eSIM.
There's a mismatch in your device's unique identifier—called an IMEI number (International Mobile Equipment Identity)—and your eSIM details after the device change. The carrier's system gets confused about which device should receive your messages.
Short code SMS are restricted while roaming in some countries.

When you contact your carrier, it helps to be very specific. You can say something like this:

“Since moving my line to an eSIM / new phone, I can receive normal SMS from friends, but verification codes from short codes (like my bank and other apps) never arrive.
I’m using Wi‑Fi Calling and/or roaming.
Can you please check if short code or premium SMS is blocked on my line and re‑provision or refresh my line for SMS and short codes, including on my eSIM?”

Ask them to:

Confirm short code / premium SMS are enabled.
Perform a line refresh / reprovision for SMS and short codes.
Re‑push eSIM settings if needed.

After they make changes, give it some time:

Wait 30–40 minutes, then request a fresh verification code.
Ideally, test with more than one app or service.

Region and roaming quirks for travelers

When you’re abroad, there are extra things that can go wrong:

Some short codes only work domestically, not when your number is roaming in another country.
If roaming is disabled on your home SIM or eSIM, the network might block all SMS, including codes.
Wi‑Fi Calling can sometimes bypass roaming issues, but only if:
- Your home line is active, and
- Your carrier supports SMS over Wi‑Fi Calling from abroad.

A travel‑friendly approach:

Keep your home SIM/eSIM active just enough to receive SMS and use Wi‑Fi Calling (even if data roaming is off).
Use a separate travel eSIM for cheap data so you’re not burning through expensive roaming data just to get codes.

When the problem is the app/service sending the code

Sometimes everything on the phone and carrier side is fine, but the app itself is the bottleneck.

Common app‑side issues:

The app blocks certain country codes or regions, especially for high‑risk services.
It doesn’t accept VoIP or virtual numbers, if that’s what you’re using.
You’ve triggered rate limits by requesting too many codes in a short time.
Your phone number was mistyped or missing the plus sign / country code.

What you can try:

Double‑check your number format in the app:
- Make sure you include the correct country code (e.g., +1, +44, +61, etc.).
- Confirm all digits are correct.
If the app offers multiple 2FA methods, try:
- Email codes instead of SMS.
- Voice call verification if available.
- Turning on app‑based 2FA (authenticator) from within the security settings.
Wait through any cooldown period (10–15 minutes) after too many failed attempts.
Contact the app’s support team and say:
- “Other SMS messages and even other apps’ verification codes arrive on my phone. Only your codes are missing. Can you check if my number or region is being blocked on your side?”

This is especially common with some fintech, crypto, or security apps that have strict rules around which regions and carriers they send to.

Safer alternatives to SMS codes for eSIM & frequent travelers

Relying only on SMS 2FA when you travel is fragile. Between roaming issues, data‑only travel eSIMs, and line changes, it’s easy to get locked out at the worst moment.

More robust options for travelers:

Authenticator apps:
Tools like Google Authenticator, Authy, or Microsoft Authenticator generate time‑based one‑time codes on your phone, with no SMS involved. They keep working even when you switch SIMs or eSIMs, as long as you still have the app.
Password managers with built‑in OTP:
Password managers such as 1Password or Bitwarden can store both your passwords and 2FA codes. When you log in, they can auto‑fill both fields, and they don’t depend on SMS or phone numbers.
Hardware security keys (for advanced users):
Devices like YubiKey let you authenticate by tapping a USB/NFC key. This is more advanced but powerful if you manage critical accounts.
Printable backup codes:
Many services (Google, Microsoft, some banks) let you generate backup codes. You can print or securely store them offline so you’re not completely stuck if your phone or SMS are unavailable.

A simple pre‑trip checklist:

Before a major trip:
- Switch your main accounts (email, cloud storage, social media) from SMS 2FA to an authenticator app where possible.
- Set up your bank’s app‑based authentication (push notifications or in‑app approval) if they offer it.
- Download and test your authenticator app while still at home, on your main Wi‑Fi.
- Generate backup codes and store them securely (password manager or printed and locked away).

This doesn’t mean you’ll never use SMS codes again, but it means a broken SMS route won’t completely block you from your digital life while you’re abroad.

Quick note on travel eSIMs and SMS verification (BitJoy context)

Most travel eSIMs, including BitJoy eSIM data plans, are data‑only plans: they give you mobile internet for apps, maps, and calls over the internet, but no local phone number for SMS or voice. That’s why they’re so affordable and easy to activate across more than 190 destinations—but it also means they cannot receive SMS verification codes or normal text messages.

Think of it this way:

Travel eSIM (data‑only):
- Pros: Cheap, fast data abroad; perfect for Google Maps, WhatsApp, Telegram, Zoom, email, hotspot use.
- Cons: No phone number, no regular calls, no SMS or verification codes.
Home SIM/eSIM (voice + SMS):
- Pros: Keeps your familiar number, can receive bank and app codes, supports calls and SMS; may work over Wi‑Fi Calling even when you’re abroad.
- Cons: Data roaming can be expensive; short codes can behave differently when roaming.

A practical setup many frequent travelers use:

Keep your home line (SIM or eSIM) active for SMS + verification codes, ideally with Wi‑Fi Calling enabled so it works in hotels and airports without burning roaming data.
Use a BitJoy‑style travel eSIM data plan for everyday internet usage—navigation, ride‑hailing, messaging apps, and remote work—without worrying about roaming bills.

Conclusion

When you mix Wi‑Fi Calling, eSIMs, and verification codes, the key thing to remember is this: codes don’t really care if your SIM is physical or electronic. They depend on the phone number on file, whether your plan actually includes SMS, and how your carrier handles short codes and SMS over Wi‑Fi or roaming.

In most cases, the eSIM itself isn’t the enemy. The real problems are misconfigured lines, disabled home SIMs, short code blocks, or apps pointing to the wrong number. Run through the basic connectivity checks, look for spam filters, try a gentle network refresh, and if codes still refuse to show up, talk to your carrier using a clear script about short codes and eSIM provisioning.

For future trips, you’ll have a much smoother time if you rely on travel eSIMs for data and shift your critical logins away from SMS 2FA to authenticator apps, password managers, or backup codes. That way, your connectivity setup stays flexible, and your access to important accounts doesn’t break every time you swap SIMs or land in a new country.

Frequently Asked Questions

Can I receive verification codes with an eSIM and Wi-Fi Calling?

Yes, if your eSIM plan includes voice and SMS, and your carrier supports SMS over Wi-Fi Calling. Data-only travel eSIMs, however, cannot receive verification texts as they lack a phone number for SMS.

Why am I not receiving verification codes on my eSIM?

This often happens because your eSIM is data-only, or your primary line for SMS is inactive/not provisioned correctly. Carriers can also block short-code verification texts, especially after switching to eSIM or when roaming.

How do verification codes (OTPs) work with SIMs, eSIMs, and Wi-Fi Calling?

Verification codes are sent via SMS to your phone number. They arrive through cellular signal or, if supported, via Wi-Fi Calling. The key is having an active voice/SMS line with your carrier; data-only travel eSIMs cannot receive these texts.

What is the difference between SMS verification codes and regular texts?

Verification codes often come from 5–6 digit "short codes," which carriers may block separately from regular SMS. This means you might receive texts from friends but still miss crucial OTPs from banks or apps.

What are common scenarios where verification codes fail with eSIMs?

Common issues include using a data-only travel eSIM (no SMS capability), incomplete eSIM provisioning by your carrier, or your phone defaulting SMS to a line that isn't active for receiving codes.

How can I check which number my verification codes are being sent to?

Check the phone number registered with the app or service, and verify on your phone which SIM/eSIM is set as the default for SMS. Ensure these match and the correct line is active.

What basic checks should I do before calling my carrier about missing codes?

Ensure your eSIM line is active with signal, Wi-Fi Calling is enabled (and the icon shows), and check your messaging app's spam folder and blocked numbers. Rebooting your phone can also help.

When is the problem likely with my carrier regarding verification SMS?

If normal texts arrive but all short-code verification texts fail, especially after switching to an eSIM or if you're roaming, it's likely a carrier-side issue like blocked premium SMS or incomplete line provisioning.

How should I talk to my carrier about not receiving verification texts?

Clearly state your eSIM is not receiving verification codes. Ask them to check if short-code or premium SMS are blocked on your line and to refresh/re-provision your line for SMS.

Can I use an authenticator app instead of SMS codes while traveling?

Yes, switching critical accounts (like banks, email) to authenticator apps (e.g., Authy, Google Authenticator) is a safer and more reliable method for 2FA when traveling, especially with travel eSIMs.

How do travel eSIMs like BitJoy's handle verification codes?

Most travel eSIMs, including BitJoy's data plans, are data-only and cannot receive SMS verification codes. They are designed for affordable internet access abroad, not for providing a phone number for texts or calls.

What's the best way to stay connected and receive codes when traveling with an eSIM?

Keep your home SIM/eSIM active for voice and SMS (using roaming or Wi-Fi Calling), and use a separate data-only travel eSIM for affordable internet access in your destination.

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