"If I add an eSIM, can I keep using my current phone number while I'm abroad?"—this is one of the most common questions we hear from people trying an eSIM for the first time. The short answer: most eSIMs used for travel and longer stays (data-only eSIMs) don't come with a phone number, so regular voice calls and SMS generally aren't available. That said, apps that run over data—like WhatsApp—can often still be used for calls and messaging. In this article, we'll untangle three things that are easy to confuse—"calls," "SMS," and "SMS verification"—and walk through how to fill the gap when you really do need a phone number, in a way that's clear even if this is all new to you.
The Short Version
- A data-only eSIM isn't assigned a phone number, so voice calls and SMS generally aren't available.
- SMS verification arrives as a "message sent to a phone number," so a data-only eSIM alone usually can't receive those codes.
- In-app calls and messages—such as WhatsApp calls—can often be used wherever you have a working data connection.
- If you need a phone number, you can fill the gap by keeping your home SIM active alongside the eSIM (dual SIM) or by using a phone-number app (VoIP). Note that VoIP numbers may not be accepted for certain verifications, such as banking.
It makes preparing for your trip far easier if you first sort out one thing: do you actually need a phone number itself, or is a data connection all you really need?
What Is a Data-Only eSIM?
A data-only eSIM is exactly what it sounds like: an eSIM that provides internet (data) only. The easiest way to picture it is as a new line you add to your phone so you can use maps, search, social media, video, messaging apps, and more.
This type of eSIM is not assigned a phone number. As a result, voice calls placed from the phone app (calling an actual phone number) and standard text messages (SMS) generally can't be sent or received. On the other hand, anything that works over a data connection—WhatsApp, Instagram messages, email, video-call apps, and so on—works just fine. For travel and shorter stays, many people find that "as long as I have data, I'm covered," and a data-only eSIM is well suited to that use.
The plans offered through Bloomy eSIM are also data-only. A phone number, SMS, and voice calls generally aren't included, but apps that run over data can be used.
"Calls," "SMS," and "SMS Verification" Are Three Different Things
What trips people up is lumping "calls," "SMS," and "SMS verification" together. In reality, each works differently.
Voice Calls
A regular voice call—dialing a number from the phone app—requires a line that has a phone number assigned to it. A data-only eSIM has no number, so this isn't available. However, "in-app calls" such as WhatsApp calls or FaceTime audio can often be used over a data connection, as long as the other person uses the same app.
SMS (Text Messages)
Standard SMS—short messages sent to a phone number—also assumes a line with a phone number. A data-only eSIM generally can't send or receive them. Day-to-day contact can often be handled through messaging apps instead, but be mindful of situations where a message "to your number" is specifically required.
SMS Verification (Two-Factor Authentication)
SMS verification is surprisingly easy to overlook. When logging in to banks, social media, or various web services, you may be asked to enter a confirmation code "sent to your phone number"—this relies on an SMS arriving at a phone-number line. With a data-only eSIM alone, you may not be able to receive that code. If you plan to log in to important services while traveling, it's reassuring to set up the measures below in advance.
What Works, and How to Fill the Gaps
| Feature | Data-Only eSIM | How to Fill the Gap |
|---|---|---|
| Data (internet, apps) | Available | — |
| In-app calls (WhatsApp, etc.) | Often available with a data connection | — |
| Voice calls (dialing a number) | Generally not available | Phone-number app (VoIP) / dual SIM |
| SMS (messages to a number) | Generally not available | Keep your home SIM active / messaging apps |
| SMS verification | Often can't be received | Keep your home SIM active / email or authenticator-app verification |
* Behavior varies by service, device, and provider. If your trip involves important verifications, check your own setup before you depart.
How to Choose When You Need a Phone Number
If you think "I might also need a phone number or SMS," it's safer not to rely on a data-only eSIM alone, but to prepare one of the following alongside it.
1. Keep Your Home SIM Active (Dual SIM)
Most recent phones support "dual SIM"—a physical SIM plus an eSIM, or two eSIMs. The idea is to keep your home line active while adding a data-only eSIM for your trip. That way you can split usage: data goes through the travel eSIM, while SMS verification and incoming calls to your number go through your home line. Keep in mind that whether your home line can receive SMS abroad—and roaming availability and charges—depend on your plan, so check with your carrier before you leave.
2. Use a Phone-Number App (VoIP)
Another option is a VoIP service that lets you get a phone number within an app. With a data connection, you may be able to make calls and exchange SMS. However, VoIP numbers may not be accepted for SMS verification at banks and some services, so it's safer not to lean on them for important verifications.
3. Switch to Email or Authenticator-App Verification
Before you travel, if the services you plan to use let you change two-factor authentication from "SMS" to an "authenticator app (one-time codes)" or "email verification," switching ahead of time makes logging in on the ground much smoother. It's a fundamental way to prepare for situations where SMS is hard to receive abroad.
The Basic Setup Flow
A data-only eSIM is generally used as follows. Since the timing of activation and other details vary by plan, be sure to also check the guidance provided at purchase.
- Install before you leave: It's reassuring to add the eSIM to your device while you still have Wi-Fi at home.
- Configure the line: Select the travel eSIM as the line used for data, and set data roaming on or off as needed.
- Start using it after you arrive: Many plans are activated for data use once you arrive. The timing of activation varies by plan.
Because the exact steps depend on your device and provider, see how to use an eSIM for details.
What to Check When You Can't Connect or SMS Won't Arrive
- Confirm that the travel eSIM is selected as the line used for data.
- Confirm that data roaming is turned on (follow your plan's guidance).
- If an SMS verification code won't arrive, remember that a data-only eSIM can't receive it in the first place—consider keeping your home SIM active or switching to an authenticator app.
- Connection quality varies with the local network, area, congestion, and device. If you have trouble connecting temporarily, try again at a different time or place.
A Few Honest Notes
- Bloomy eSIM is a data-only eSIM. A phone number, SMS, and voice calls generally aren't included (apps that run over data can be used).
- A phone-number app (VoIP) may not work for SMS verification at banks and some services. For important verifications, keeping your home SIM active or using an authenticator app is more reliable.
- Connection quality and the specifications of each service may vary or change depending on local network conditions, your device, and the provider. Plan details may also change, so please check the latest information before purchasing. A fair-use policy applies.
What You Can Do With Bloomy eSIM
If "all I really need is data" describes you, you can choose a plan to match your destination, data allowance, and number of days. Sorting out in advance whether you need a phone number or SMS makes it easier to prepare what's right for you. To check eSIMs for your destination, use the eSIM comparison page to find a plan by country, data allowance, and length of stay.
Related Links
- Pre-Departure Checklist: Preparing Data (eSIM) and a Phone Number
- What to Do When You Can't Receive SMS Verification Abroad
- How to Use an eSIM
- eSIM Comparison Page
In Summary
A data-only eSIM is a convenient, easy way to set up internet access abroad, but it's a different thing from a "phone number," "SMS," and "SMS verification." You may rarely run into trouble with data, yet situations that need a call to a number or SMS verification come up more often than you'd expect. Start by sorting out how you'll use it, and if needed, prepare to keep your home SIM active or switch to an authenticator app before you travel. For the full picture of what to prepare, the Pre-Departure Checklist: Preparing Data (eSIM) and a Phone Number is a helpful reference.
