Last updated: July 26, 2026
If you use a regular SIM from your mobile carrier back home, you have probably wondered whether it is safe to simply carry it abroad, or whether charges could quietly pile up without you noticing. Here is the short answer: turn off data roaming on your home-country line before you leave, and arrange a separate connection for the country you are visiting. That is the approach with the fewest things to second-guess. You do not need to cancel your contract or give up your phone number. This article walks through the settings worth checking on both iPhone and Android, and the order to do things in — from the night before departure to the moment you land. (Information as of July 2026.)
- Turn data roaming off before you fly
- Keep your number, switch only the data
- Add the eSIM before departure, turn it on after landing
- Choose which line carries data in Settings
- Follow a set order when nothing connects
Before you fly, decide where your data will come from
The conclusion first: there is not much to prepare. (1) Turn off data roaming on your home-country line. (2) Pick one way to get data at your destination. (3) Finish the setup before you leave. Do those three things and the only job left on arrival is switching a line on.
The order matters, because if you fly without deciding how you will connect, you end up researching options with no signal at all. Free airport Wi-Fi can be crowded and slow, and starting the whole process there takes time. Sort it out beforehand and maps or ride-hailing apps work the moment you land.
- Turn data roaming off: this stops your home-country line from automatically latching onto a local network abroad
- Pick how you'll connect: international roaming, a local SIM, or an eSIM
- Finish the setup: with an eSIM, adding it to your phone before departure saves worry later
Three main ways to get connected abroad, and who each one suits
For short trips and business travel where "data is enough", adding an eSIM that covers your destination usually involves the fewest steps. What changes the answer is whether you also need calls and SMS tied to a phone number.
| Option | Best for | Things to watch |
|---|---|---|
| International roaming on your existing line | You'd rather not add any new setup / you only need a short burst of data | Availability, pricing, and whether you have to sign up in advance all differ by plan. Check your operator's official information for your specific plan before you leave |
| Buying a local SIM after you arrive | Longer stays where you also want a local number | You have to find a store after landing, and you'll need a SIM pin plus somewhere safe to keep your original SIM |
| Adding an eSIM for your destination | You want everything ready before departure / data is your main use | Requires an eSIM-compatible phone. It is data-only, so calls and SMS over a phone number need a separate solution |
For the bigger picture of pairing your existing home-country plan with a travel eSIM — who it suits, roughly what it costs, and how the day itself goes — see Travelling abroad on your existing plan: how an eSIM solves mobile data. This article zooms in on just one part of that: checking your settings before departure.
If you are not sure whether your phone supports eSIM, it helps to look at the eSIM-compatible devices page first so you know where you stand.
What to check, on iPhone and on Android
There are only two things to confirm: that data roaming is off, and which line is carrying your mobile data. Menu wording varies between operating system versions and phone models, so look for the closest matching label.
iPhone: turning data roaming off
Go to Settings → Cellular (Mobile Data) → tap the line name for your home-country plan → switch Data Roaming off. If you have several lines registered, each one has its own setting, so select your home-country line first and check it there to be sure.
iPhone: choosing the right line after adding an eSIM
Once the eSIM is added, two lines appear on the Cellular screen. Under Cellular Data, select the line you want to use at your destination and data will flow over that one. It is worth turning Allow Cellular Data Switching off as well, so your phone doesn't hop back to your home-country line unintentionally.
Android: data roaming and SIM priority
Go to Settings → Network & internet → SIMs → the line in question → switch Roaming off. At the same time, set the line used for Mobile data to the one you'll be using abroad. Depending on the manufacturer, this section may be called "Dual SIM" or "SIM management".
Android: APN settings are usually automatic
In most cases, adding an eSIM configures the connection settings automatically. Only if data isn't working do you need to check them manually, following the instructions you were given. Step-by-step details are on the setup guide.
Which countries international roaming covers, what it costs, and how you sign up all vary by operator and plan — and they change over time. For "how much will this cost me", check your own operator's current official information. This article does not quote price estimates.
From the night before to after you land
Getting the work done the night before makes travel day much lighter. With Bloomy, the setup link you receive adds the eSIM to your phone in a single tap.
The night before: add the eSIM
On a Wi-Fi connection, tap the setup link you received once and follow the on-screen prompts to add the line. You don't have to switch the line on at this stage (when activation starts depends on the plan, so check the information provided at purchase). If your phone has trouble reading the link, adding the eSIM by QR code or manual entry is also available.
At the airport and on board: turn your home line's data off
Before boarding, confirm once more that data roaming on your home-country line is off. Even with airplane mode on, which line connects when you switch it back off comes down to your settings.
After landing: switch the eSIM line on
Once you arrive, turn the eSIM line on and check that Cellular Data / Mobile data is pointing at that line. It can take a moment for the display to update, so wait a minute or two, or toggle airplane mode on and off once.
Who this approach suits, and who it doesn't
To be straight about it, this isn't the right fit for everyone.
A good fit if you…
- Want to keep your usual number and contract exactly as they are
- Only need maps, search, social media, and app-based calls
- Don't want to deal with paperwork after you arrive
- Are on a short trip or business travel and want to pick only what you'll use
Less of a fit (worth looking at other options too) if you…
- Need to make or receive calls and SMS on a phone number while abroad
- Have a phone that doesn't support eSIM
- Are staying long-term and want a local phone number
What to check, in order, when you can't connect
Rather than changing settings at random, work down this list — it's faster.
- Is airplane mode off?
- Is the line you added switched on?
- Is Cellular Data / Mobile data set to the line you added?
- Is data roaming on your home-country line still off?
- Turn airplane mode on, wait about ten seconds, then turn it back off
- Restart the phone
Keep in mind that speed and stability vary with local network conditions, coverage in your area, your device, and how busy the network is at the time. Signal can weaken deep inside buildings, underground, or while you're moving. If none of the above helps, further steps are on the troubleshooting page.
Calls and messaging on a data-only eSIM
The short answer: app-based calling works just as it normally does. Bloomy eSIMs are data-only, but calls that run over data — WhatsApp, Messenger, FaceTime and similar — work as usual. What you don't get is calling and receiving on a phone number (voice calls) and SMS. Data-only plans are also subject to a fair usage policy, so it's worth reading the plan details before you buy.
For staying in touch with family and friends, or calling someone you're travelling with, app calls are enough in most situations. If you have something planned that requires receiving a call or an SMS on a phone number, though, it's worth also checking your existing operator's roaming terms or a plan that includes a number. Terms around numbers and SMS differ from operator to operator, so check the latest information from yours if this matters to you. If you're unsure, the FAQ may help.
Finding a plan for your destination
If you already know where you're going, the eSIM comparison page lets you search by country, data allowance, and number of days. Available plans, prices, and terms of use can differ by country and region, so please check the current listings on the comparison page before purchasing.
If you're unsure about data size: lean smaller if you mostly use maps and messaging, larger if you watch video or spend long stretches on calls. Choosing based on what you actually need keeps things comfortable. Details on adding more data if you run short are included in the information you receive after purchase.
In summary: three settings, all done before you leave
When you travel abroad on your home carrier's SIM, there are three things to do: turn off data roaming on your home-country line, decide how you'll get data at your destination, and finish the setup before departure. You don't have to give up your number or your contract — think of it as switching only the data over for the trip.
As a next step, check whether your phone supports eSIM, then take a look at plans for where you're heading. If you'd like to review the whole process again, Travelling abroad on your existing plan: how an eSIM solves mobile data covers it end to end.
The information in this article was verified as of July 2026. The names of settings screens may differ depending on your device and operating system version. Operator plan terms, international roaming conditions, and covered countries are also subject to change. Please check the latest listings and official information from your provider before purchasing and before you travel. Bloomy eSIMs are data-only: no phone number, SMS, or voice calls. A fair usage policy applies, and connection speed and stability vary with the local network, your device, and your location.
