Most prepaid travel eSIMs do not have a phone number. They are data only plans: they give your phone mobile internet in another country, and you make calls and send messages over that internet using apps you already have. This surprises a lot of first time buyers, so it is worth understanding exactly what you get and what you keep from your existing line.
The short version is that a travel eSIM replaces expensive roaming data, not your identity as a phone user. Your own number, with all its contacts, banking codes and messaging history, stays exactly where it is on your home SIM. The eSIM simply carries the data.
This guide explains why travel eSIMs work this way, how to keep your real number ringing while you travel, and the handful of situations where you might actually want an eSIM that does include a local number.
In this guide:
- Why most travel eSIMs are data only
- How you call and text on a data only eSIM
- Keeping your own number active abroad
- When you actually want an eSIM with a number
- Setting up both lines the right way
Why most travel eSIMs are data only
A travel eSIM is designed to solve one problem cheaply: getting affordable, fast mobile data the moment you land. Voice and SMS on a traditional cellular network require the provider to allocate you a number on a specific carrier and route calls through the legacy voice system, which adds cost and regulatory overhead in every country. Data does not need any of that.
By selling data only plans, providers can offer connectivity in dozens of countries at a fraction of roaming prices, activate it instantly by QR code, and let you install it before you even leave home. The trade off is that the plan has no dialable number attached. For the overwhelming majority of travellers this is not a limitation at all, because the way we actually contact people abroad has almost entirely moved to internet based apps.
If the concept of a data only line is new, our complete guide to what an eSIM is covers the fundamentals, and the eSIM glossary entry gives the one paragraph definition.
How you call and text on a data only eSIM
With mobile data flowing from your travel eSIM, every communication app on your phone works normally. You are simply routing calls and messages over the internet instead of the cellular voice network. In practice this covers essentially everyone you need to reach.
| What you want to do | How to do it on a data only eSIM |
|---|---|
| Message friends and family | WhatsApp, iMessage, Messenger, Telegram, Signal |
| Voice call home | WhatsApp, FaceTime Audio, Messenger, Signal |
| Video call | FaceTime, WhatsApp, Zoom, Google Meet, Teams |
| Call a hotel or restaurant abroad | Skype credit, Google Voice or your home line for the odd call |
| Receive a banking or 2FA code | Your home number, kept active alongside |
The one thing internet apps do not do is receive a call or SMS sent to your regular phone number. That is what your home line is for, and the good news is you do not have to choose between the two.
It is worth being clear about what actually changes when you contact someone. On a data only eSIM, a WhatsApp or FaceTime call still shows up on the other person’s phone under your usual name and account, because your messaging identity is tied to your registered number and app account, not to whichever SIM is currently carrying the data. So friends and family see the same contact they always do; nothing about how you appear to them changes just because the underlying data comes from a travel plan. The only difference is on your side, where you are routing over the internet instead of the cellular voice network, and in practice you will not notice that difference at all on a decent connection. This is why the vast majority of travellers never miss having a dialable number on the travel plan itself: everyone they care about is reachable through the same apps and the same identity they use at home.
Keeping your own number active abroad
Modern phones hold two lines at once, and this is the setup we recommend for almost every traveller. You keep your home SIM or eSIM installed and switched on for calls and texts, and you add the travel eSIM for data. Your number keeps working, your codes keep arriving, and you pay nothing for roaming data because all the data comes from the eSIM.
The critical setting is data roaming. Leave your home line enabled for calls and texts, but turn its data roaming off so it never quietly connects to an expensive foreign network. Set the travel eSIM as your data line, and you are done. Our dual SIM travel setup guide walks through the exact toggles on both iPhone and Android, and the keep your WhatsApp number abroad guide explains why your messaging identity never changes even though your data does.
This is also the safest arrangement for anyone who relies on SMS security codes. Banks, airlines and government apps still text your normal number, and because that line stays live, nothing about your logins breaks while you travel.
When you actually want an eSIM with a number
Data only suits short trips perfectly, but there are cases where a dedicated local number earns its place:
- Long stays and relocations. If you are living somewhere for months, a local number makes deliveries, appointments, banking and ride hailing far smoother than an app only setup.
- Frequent local voice calls. Some businesses, especially smaller ones abroad, only take standard phone calls, and a local number saves fumbling with internet calling for every reservation.
- A number you can hand out. Digital nomads settling into a city often prefer a local mobile identity for classifieds, local services and new contacts.
For these, look specifically for a plan that lists a number as included. Many longer stay and regional eSIM options do, and the listing will always say so. For a two week holiday, though, a data only plan plus your existing number is simpler, cheaper and completely sufficient.
Setting up both lines the right way
Getting this right takes about two minutes and prevents the two most common mistakes: accidentally roaming on the home line, or losing incoming calls because the home line was removed.
- Install the travel eSIM before you fly, while you still have Wi-Fi, following the install and activate walkthrough.
- Keep your home SIM or eSIM in the phone and leave it enabled for calls and texts.
- Turn data roaming off on the home line.
- Set the travel eSIM as the default line for mobile data.
- Confirm your favourite calling apps are installed and signed in before departure.
Done this way, your phone behaves exactly as it does at home: your number rings, your messages arrive, your security codes come through, and your data is fast and cheap because it comes from a prepaid travel plan rather than a roaming meter.
Travel data eSIM plans from Viasimo are one off prepaid purchases with instant email delivery and QR install in minutes, and they sit happily alongside your existing number rather than replacing it. Browse the destinations page to see live plan sizes and prices for your route, and travel with your real number in your pocket and affordable data in the air.
