Last updated: August 2026
If you have been shopping for a travel eSIM, you have probably run into the phrase “data-only.” And that is usually where the doubt creeps in: “If it is data-only, does that mean WhatsApp calls stop working too?” When your family and friends are all reachable through a messaging app, leaving that question unanswered makes it hard to finish planning the trip. Here is the short answer: voice and video calls in WhatsApp work normally on a data-only eSIM. The only things you lose are calls made to or from a phone number, and SMS text messages sent to a phone number. Below we walk through why that is, what to keep an eye on in daily use, what to check when a call gets choppy, and what to set up before you fly.
- App-based calls work fine
- Only number calls and SMS are out
- Video calls use noticeably more data
- A step-by-step fix list for bad calls
- What to sort out before departure
Yes — app calls work on a data-only eSIM
Voice calls and video calls in WhatsApp run normally on a data-only eSIM. The reason is simple: those calls travel over your internet connection, not over a voice phone line. As long as data is flowing, the calling features work right along with everything else.
The same logic applies to Facebook Messenger, Signal, Telegram, FaceTime, Zoom, Google Meet and similar apps — all of them are just data. What you cannot do on a data-only eSIM is place or receive a call to an actual phone number, or send and receive SMS messages tied to a phone number. People often compress this into “you can't make calls,” which sounds far more limiting than it is. It is much clearer to remember it as: those two things, and nothing else.
If you want the underlying explanation of how data-only eSIMs work and how they differ from plans with voice and SMS, see What Is a Data-Only eSIM? Voice and SMS Explained Simply. This article zooms in on one specific everyday situation: making app calls to the people back home.
What works and what doesn't, at a glance
Seeing the whole picture first makes the decision easier. Here is how each way of staying in touch behaves while you are on a data-only eSIM.
| Way of staying in touch | On a data-only eSIM | Notes |
|---|---|---|
| WhatsApp voice calls | Works | Runs over your data connection |
| WhatsApp video calls | Works | Uses more data than voice |
| WhatsApp chats and photo sharing | Works | Just as you'd use it at home |
| Messenger, Signal, Telegram calls | Works | Same data-based mechanism |
| FaceTime (audio and video) | Works | Requires an Apple ID |
| Calls to or from a phone number | Not available | The plan doesn't include a number |
| SMS sent to a phone number | Not available | Plan an alternative in advance |
Banks, payment services and some websites may send a one-time code by SMS to your phone number. A data-only eSIM cannot receive those messages. Before you travel, check each service's official guidance on whether you can switch to an authenticator app, and consider keeping your home-country number active so it can still receive texts. The rules differ from service to service and do change over time. Our articles on phone numbers and SMS go into more detail.
How much data do app calls actually use?
The rule of thumb: voice calls are fairly light, video calls are heavy. Exact consumption depends on the app's settings, the video quality and the network you're on, so it's safer not to lock yourself to a single number. As a general sense of scale:
| Activity | Data usage | How to handle it on a trip |
|---|---|---|
| Chats and photos | Light | Use freely without much thought |
| App voice calls | Fairly light | Good for quick check-ins on the move |
| App video calls | Heavy | Pair with hotel Wi-Fi for peace of mind |
| Streaming video, long map sessions | Very heavy | Where most of your data really goes |
When travellers run out of data, the culprit is rarely calling — it's usually video streaming or leaving a maps app running for hours. Keeping family check-ins to voice calls makes your allowance much easier to predict. Save the long catch-ups and video calls for the evening, when you're back at your accommodation and on Wi-Fi.
When calls drop or won't connect: what to check
Unstable calls almost always come down to a device setting or the signal where you happen to be standing. Before you buy anything else, work through this list in order.
- Confirm data is working at all: try loading a web page in your browser. If nothing loads, the issue is with the connection itself, not with calling.
- Check which line is selected: on a phone with more than one line installed, make sure mobile data is set to the line you intend to use.
- Check data roaming: some plans require it to be switched on. Follow the instructions provided with your purchase.
- Toggle airplane mode off and on: often nothing is broken — the phone simply needs to reconnect to the network.
- Review Low Data Mode and battery saver: when these are on, call quality may be deliberately reduced.
- Check your remaining data: once the allowance is used up, the connection stops.
- Try a different place or time: underground, deep inside buildings and at busy tourist sites, signal is weaker or the network is congested.
Connection quality varies with the local network, the coverage area, your device and how busy the network is at that hour — the same spot can feel different in the morning and the evening. If a call feels sluggish, turning the video off and continuing with voice only usually helps straight away. For a more detailed walkthrough see our troubleshooting page, or the setup guide if you want to revisit your initial configuration.
Who this suits — and who should plan a bit more
Being upfront here saves a lot of “this wasn't what I expected” after purchase.
| A good fit if… | Worth arranging a backup if… |
|---|---|
| You reach family and friends mainly through messaging apps | You expect to phone local restaurants or hotels by number |
| You're travelling, on business or staying short-term and want to keep costs down | You need to receive SMS verification codes while abroad |
| Your usage is mostly maps, translation and social media | You need calls to your home-country number to reach you overseas |
| You're arriving for study or a long stay and want connectivity from minute one | Your work depends on being reachable on a phone number |
Even if the right-hand column describes you, a data-only eSIM is still perfectly usable. A common solution is to keep your existing home line active for calls and texts while letting the eSIM handle all the data. Check what your own contract allows with your mobile carrier at home before you leave.
What to sort out before you fly
There are three things to do, and all of them are easy to handle calmly at home.
1. Check that your phone supports eSIM
Start here. You can confirm your model on our eSIM-compatible devices page. A carrier-locked phone may not be able to use a third-party eSIM, so it's worth checking that at the same time.
2. Install the eSIM before departure
With Bloomy, installation starts with a single tap on the setup link you receive. Follow the on-screen steps to add the eSIM, then switch the line on once you land. Getting the installation done while you still have reliable Wi-Fi at home means you won't be hunting for a network at the airport. Activation timing can differ between plans, so check the instructions that come with your purchase.
3. Agree on how people will reach you
Since number-based calls won't work while you're away, tell family and colleagues in advance: “message me on WhatsApp.” It's also worth nominating one person who will always be reachable in the app, so you have a clear line of contact if something goes wrong.
How to think about choosing a plan
If app calls are your main use, you often don't need an unusually large allowance. Three questions make the choice straightforward: where you're going, how many days you'll be there, and roughly how much you'll use per day. If you stream video or keep maps open for long stretches, give yourself some headroom.
You can browse what's available for your destination on the eSIM comparison page, filtered by country, data allowance and number of days. For longer stays where you'd rather not watch the counter, the unlimited plan page is another option — though even unlimited plans come with a fair use policy, may have reduced speeds after a certain level of use, and differ on whether tethering is allowed. Check the conditions before you buy.
Plan contents, prices and supported countries can change, so the comparison page is always the most reliable place to see current details, including the price at the time of purchase. Questions about ordering and payment are covered in our FAQ.
In summary
On a data-only eSIM, WhatsApp voice and video calls work exactly as they normally do. The only two things you give up are calls to and from a phone number, and SMS sent to a phone number. Once that's clear, there's very little left to worry about when it comes to staying in touch abroad.
Your next steps: confirm your phone supports eSIM, and look at the plans that match your destination and trip length. If you're likely to need SMS verification codes, arrange one alternative before you go — and you're essentially ready. Start with the comparison page to find a plan for where you're heading.
Note: this article reflects information available as of August 2026. Plan contents, prices, supported countries and terms of use may change. Please check the latest details before purchasing.
