You have found the perfect eSIM deal for your trip. The price is right, the data allowance looks generous, and setup takes five minutes. Then you notice something in the fine print: "data only." Wait, does that mean you cannot make calls or send texts? Will your friends and family be able to reach you? Here is exactly what a data only eSIM does, what it does not do, and how to make sure you are never cut off while traveling.
What "Data Only" Actually Means
An eSIM is a digital SIM card. Instead of a plastic chip you pop into your phone, the carrier profile is stored electronically inside your device. Functionally, though, a data only eSIM works just like a normal SIM for internet purposes. You get mobile data for browsing, maps, social media, and streaming, but the profile has no phone number attached to it, so it cannot send or receive SMS text messages or make or receive regular phone calls.
This is not a limitation of eSIM technology itself. The GSMA standard that eSIMs are built on fully supports voice calls and SMS, plus extras like call forwarding. But most eSIMs sold to travelers are set up as data only on purpose. Travelers mainly need internet access when abroad, and skipping the voice and SMS setup keeps the eSIM simpler and cheaper to provide. That is why data only plans are so common among travel eSIM providers, including on our global eSIM plans that cover multiple countries on one profile.
How to Keep Your Calls and Texts While Using a Data eSIM
The good news is that switching to a data eSIM does not mean giving up your regular phone number. Most travelers run both at the same time, and it is easier than it sounds.
Your Phone Can Run Two SIMs at Once
Most phones made in the last several years, including iPhones from the XS and XR generation onward and most mid-range and flagship Android phones, support something called Dual SIM Dual Standby. In plain terms, this means your phone can keep two SIM profiles active at the same time. One handles your data, and the other handles your calls and texts, and they work independently without interfering with each other.
In practice, that means you leave your home carrier's physical SIM card in your phone and install your travel eSIM alongside it. Your home SIM still handles calls and texts on your usual number, while the eSIM quietly takes care of your internet. If you are not sure whether your specific phone supports this, check our eSIM compatible devices guide before you travel. Our eSIM setup guide walks through installing and switching between profiles step by step.
Data Roaming and Call Roaming Are Two Different Settings
This one trips up a lot of travelers. On your phone, "data roaming" is a separate toggle from voice and text roaming. When you turn off data roaming on your home SIM to avoid roaming data charges, you are only switching off its internet connection. Calls and texts on that number generally continue to roam and arrive normally, because they travel over a different part of the network than data does. In most cases your carrier just needs a roaming agreement in that country and your phone needs signal, and your calls and texts should keep coming through as usual. Policies vary slightly from one provider to another, so check your specific carrier's roaming terms if you want to be certain before you go.
What Still Works Perfectly Fine on a Data Only eSIM
Most of the messaging and calling people actually rely on these days does not need a phone number at all. Apps like WhatsApp, iMessage, Telegram, Signal, and Facebook Messenger send messages and make calls over an internet connection, whether that is WiFi or mobile data. Your data only eSIM handles all of this without any issue, since these apps were built to run over data in the first place.
So if most of your communication already happens through one of these apps, a data only eSIM alone may cover everything you need. It is really only traditional carrier based calls and SMS that require a separate number, and that is where keeping your home SIM active becomes useful.
What Might Not Work, and Why
There are two situations where a data only eSIM alone can leave you stuck. Both are easy to plan around once you know they exist, and neither should catch you off guard if you think about them before you land. The first involves security codes sent by text, and the second involves apps or services that expect a local phone number.
The first is SMS verification codes, often called OTPs, that banks and other services send to confirm your identity. These codes travel over the traditional SMS network to a specific phone number, and since your data eSIM has no phone number attached, it cannot receive them. The fix is simple: as long as your home SIM stays in the phone and is not suspended, those OTP codes generally still land on your usual number, since SMS delivery does not depend on which SIM is handling your data. That said, a small number of banks or services do treat a number that appears to be roaming abroad differently, so check with your bank before you rely on it during an important transaction.
The second is apps and services that ask for a local phone number. Some banking apps, ride hailing apps, and restaurant booking platforms prefer or require a number with the local country code, and may reject or flag a foreign number during sign up. This does not happen with every service, and it is impossible to predict in advance which ones will ask for it, but it is a real pattern travelers run into often enough to plan around. Keeping your home SIM active for verification purposes, or checking a service's requirements ahead of time, avoids the frustration of being locked out mid trip.
Putting It Together for Your Trip
For most destinations, the setup that works best is simple: install a data eSIM for reliable, often much cheaper internet, and leave your home SIM in place for calls, texts, and anything that needs your real number. If you are heading somewhere with a lot of countries on one itinerary, say a multi stop trip across Europe, a data only eSIM that covers the whole region saves you from juggling a new SIM at every border, while your home SIM quietly stays on standby for anything that needs it.
Data allowances matter too, especially with plans labeled "unlimited." Our guide on what unlimited really means for travel eSIM data explains the fair use limits that usually sit behind that word, so you know what you are actually getting.
Helpful Tips
- Check your phone supports Dual SIM Dual Standby before you travel, especially if it is an older model.
- Install your travel eSIM a day or two before departure so you are not troubleshooting at the airport.
- Leave data roaming off on your home SIM but keep the SIM itself active, so texts and calls still arrive without the roaming data charges.
- Tell your bank you are traveling and confirm how they send verification codes, especially if you plan to make purchases abroad.
- Set your eSIM as the primary line for data and your home SIM as primary for calls and texts, so your phone does not default to the wrong network for each task.
Common Mistakes
- Removing or deactivating the home SIM entirely, which also cuts off calls, texts, and OTP codes along with the roaming data charges.
- Assuming a data only eSIM will let you receive bank verification texts, when it has no phone number to receive them on.
- Not checking device compatibility first and discovering mid trip that an older phone cannot run two profiles at once.
- Forgetting to turn data roaming back on, or off, correctly when switching between the eSIM and home SIM for different tasks.
- Assuming every app or service is fine with a foreign number, then getting stuck signing up for something that needs a local one.
Frequently Asked Questions
Can I make normal phone calls with a data only eSIM?
No, a data only eSIM has no phone number attached, so it cannot make or receive traditional calls or SMS texts. You can still make calls through apps like WhatsApp or FaceTime that run over the internet, since those use your data connection rather than the phone network.
Will people still be able to text or call my normal number while I travel?
Generally yes, as long as your home SIM stays in your phone and your carrier has a roaming agreement in the country you are visiting. Turning off data roaming on that SIM only stops its internet access, it does not stop calls and texts from reaching it.
Do I need a dual SIM phone to use a data eSIM and keep my home number?
You need a phone that supports Dual SIM Dual Standby, which most phones from around 2019 onward do, including recent iPhones and most Android models. You can check our device compatibility guide to confirm your specific model before you buy.
Why do most travel eSIMs not include a phone number?
The eSIM standard itself supports voice and SMS, but travel eSIM providers mostly sell data only plans because that is what travelers need most, and it keeps the eSIM simpler and more affordable to offer. If you want to see how we test and compare these plans, our article on how we test eSIMs explains our process.
What happens if I do not have my home SIM active at all?
Without a home SIM in the phone, you lose access to your usual phone number entirely, including calls, texts, and any SMS verification codes tied to it. A data only eSIM cannot substitute for that number, so keeping your home SIM active alongside your travel eSIM is the simplest way to avoid that gap if you rely on SMS codes for banking or other accounts.
Conclusion
A data only eSIM is not a downgrade, it is simply built to do one job well: give you fast, affordable internet wherever you land. Pair it with your home SIM sitting quietly in the background for calls and texts, and you get the best of both without paying for a voice plan you barely use abroad. If you are planning your next trip, take a look at our current global eSIM plans to see coverage and pricing before you go.