Last updated: August 31, 2026 (the information in this article was verified as of August 2026)
One of the most common worries before a trip is landing abroad and having your phone quietly latch onto a local network without you noticing. The short answer: switch your home line — the plan you use with your mobile carrier at home — to mobile data off + data roaming off, and let a travel eSIM handle all your data. With that setup, unintended roaming is far less likely to happen. This guide walks through the settings on both iPhone and Android, in the order you'll actually need them: before departure, after you land, and once you're back home. Even if this is your first time using an eSIM abroad, following the steps in order should keep things straightforward.
- You only need to switch off your home line
- Roaming on the eSIM side may need to stay on
- Set it up before you go, switch over on arrival
- How to restore your home line afterwards
- Data-only still lets you make app-based calls
The short version: turn off your home line, leave the eSIM on
There are really only two things to get right. First, turn off mobile data and data roaming on your home line. Second, set your travel eSIM as the line used for mobile data. Once both are done, the eSIM is the only line carrying data while you're abroad.
The step people most often get wrong is assuming that data roaming should be switched off everywhere. Most travel eSIMs work by connecting to partner networks in the country you're visiting, which means data roaming on the eSIM side may need to stay on. Remember it as: you only turn roaming off on your home line. A surprising share of "I set it all up and still have no data" cases come down to roaming having been switched off on the eSIM too.
It's also worth knowing that your carrier's international roaming and a travel eSIM are priced and suited to different kinds of trips. If you'd like the bigger picture before you start tapping through settings, our comparison of carrier international roaming vs. a Bloomy eSIM — how the pricing works and how to choose makes it clearer why these steps are set up this way. Note that roaming activation requirements and terms can change, so always confirm the current details on your own carrier's official site.
Three things to do before you leave
1. Check that your phone supports eSIM
Start by confirming your smartphone supports eSIM. Even on an eSIM-capable model, a handset bought through a carrier may be locked in a way that prevents you from adding another operator's line. This is a painful thing to discover the night before a flight, so give yourself time and check on our eSIM-compatible device list well in advance.
2. Install the eSIM while you're still at home
Adding (installing) an eSIM requires an internet connection, typically Wi-Fi. If you wait until you arrive, you'll be trying to install it with no connectivity — which usually means hunting for airport Wi-Fi first. Doing it on your home Wi-Fi before departure is far less stressful.
With a Bloomy eSIM, the setup link you receive after purchase installs the eSIM in a single tap, with on-screen prompts guiding you through. You don't need to turn the line on at that point; the normal flow is to install now and activate once you land. Full instructions are in our setup guide.
3. Decide what to do with your home line
Data will be handled by the eSIM — but whether you switch your home line off entirely or leave it on to receive calls depends on your trip. It's a different decision depending on whether you need to stay reachable on your home-country number. The quick-reference table below will help you settle it before you fly, so you're not fiddling with settings on arrival.
The data roaming setting only governs data. Voice and SMS roaming are handled separately, and with some plans simply receiving a call while abroad can incur a charge. If incoming calls matter to you as much as data usage, check the current terms in your carrier's official documentation before you travel.
Step-by-step: iPhone and Android
On iPhone
- Open Settings → Cellular (or Mobile Data).
- From the list of lines, select your home line and switch off Turn On This Line. If you want to keep receiving calls, leave the line on and switch off Data Roaming for it instead.
- Go back to the list, select your travel eSIM and switch on Turn On This Line.
- In that eSIM's settings, switch on Data Roaming (travel eSIMs may rely on this setting to connect to local networks).
- Return to the Cellular screen and set your travel eSIM as the line for Cellular Data.
- On the same screen, switch off Allow Cellular Data Switching. If this stays on, your phone can fall back to your home line whenever the eSIM's signal drops.
On Android
- Open Settings → Network & internet → SIMs (depending on the model, this may be called Mobile network or similar).
- Select your home line and either switch off Use SIM or switch off Roaming.
- Select your travel eSIM, enable it, and switch on Roaming.
- Set the travel eSIM as the SIM used for Mobile data.
Android menu names and their order vary by manufacturer and OS version. The equivalent options are usually tucked inside a menu labelled SIMs, Mobile network or Dual SIM — so if the wording doesn't match exactly, take a moment to look around rather than assuming the option isn't there.
Quick reference: home line vs. travel eSIM
| Setting | Home line (your usual carrier) | Travel eSIM | Notes |
|---|---|---|---|
| Line on / off | Off (on, if you want incoming calls) | On | If you don't need calls, off is simplest |
| Mobile data | Not used | Select this line | Keep all data on the eSIM |
| Data roaming | Off | On (where required) | Only the home line gets switched off |
| Default voice line | Leave as home line | Not used | A data-only eSIM isn't used for voice |
| Allow cellular data switching (iPhone) | Off | Prevents unintended data on your home line | |
Who this approach suits — and who it doesn't
Being clear about fit up front makes the choice much easier.
A good fit if you
- Mainly use maps, search, social media and app-based calls while abroad
- Know your destination and dates, and want to buy only what you need
- Prefer to have your phone configured before you leave
Less of a fit (consider combining with something else) if you
- Need to make and receive calls and texts on your home-country number exactly as usual while travelling
- Might need SMS verification codes or a working number for your bank back home or for official procedures
- Have a device that doesn't support eSIM, or can't confirm whether it's carrier-locked
If any of those apply, a combination usually works better: leave your home line on for incoming calls, or look separately at a plan that includes a phone number.
What to keep in mind with a data-only eSIM
A Bloomy eSIM is data-only, and since this is easy to misread, here it is plainly: what you can't do is make or receive regular phone calls or SMS on a phone number. App-based calling over data — WhatsApp, Messenger, FaceTime and the like — works as normal. It isn't the case that you lose the ability to call anyone.
If you do want to receive calls or texts on your home-country number, one option is to leave your home line switched on and turn off only its data roaming. Voice and SMS roaming may be billed separately, though, so check the conditions in your carrier's official information before deciding.
Two more things to note: unlimited-style plans are subject to a fair usage policy, and connection speed and quality vary with the local network, your device, and the area and congestion where you are. No eSIM can guarantee identical performance everywhere.
If you can't get online after you land
When everything looks configured but there's still no data, working through these in order usually isolates the cause.
- Turn on airplane mode for about 30 seconds, then turn it off.
- Restart the device (this often settles things right after a line switch).
- Confirm Data Roaming is switched on for the eSIM.
- Confirm the line selected for mobile data is the eSIM.
- Confirm network selection is set to Automatic. If you've selected a network manually, switch back to automatic.
- Confirm your plan's start date has arrived and the validity period is active.
If none of that helps, our troubleshooting page has checks organised by symptom. For questions about buying or setting up a plan, see the FAQ.
Restoring your home line when you get back
Once you're home, put things back. On iPhone, go to Settings → Cellular, switch your home line back on, and set it as the line for Cellular Data. On Android, do the same: re-enable the home line and set it as the mobile data SIM. If you're done with the travel eSIM, you can switch it off or delete it from the device.
If the internet feels slow or unavailable after you return, it's often because mobile data is still pointed at the travel eSIM. Checking before you leave the airport saves a frustrating journey home.
In summary: configure before you go, switch after you land
Boiled down, it's four steps: (1) check device compatibility and install the eSIM before departure; (2) on arrival, turn off mobile data and data roaming on your home line; (3) set mobile data to the travel eSIM; (4) restore your home line when you get back. Nothing here is technically difficult — once you know the order, it takes a couple of minutes.
If your destination is already decided, use the Bloomy eSIM comparison page to find a plan by country or region, data allowance and number of days. To walk through the setup again, see the setup guide, and for a broader look at staying connected abroad, browse our eSIM guide articles.
This article is based on information verified as of August 2026. Plan contents, pricing (shown in USD), terms and the names of settings menus on your device may change — please confirm the current listings on our comparison page, and check your own carrier's official information, before purchasing or travelling. Bloomy eSIMs are data-only: they do not include a phone number, SMS or voice calling. Unlimited-style plans are subject to a fair usage policy. Connection speed and quality vary depending on the local network, your device, and the area and network congestion where you are.
