When you use an eSIM abroad, most plans require you to turn data roaming ON for the eSIM that holds your destination travel plan. The phrase "roaming" often triggers worries about huge bills, but a travel eSIM like Bloomy works on a prepaid model: you use it within the data and validity period you purchased. Turning roaming on does not automatically rack up surprise charges. There's really just one thing to remember: turn roaming ON for the eSIM you're actually using (your destination plan), and turn roaming OFF on your regular home SIM. This guide walks you through why the settings work this way, the step-by-step process for both iPhone and Android, and what to check when you can't connect — laid out so first-timers can follow along in order (information current as of June 2026; on-screen labels may change with device or OS updates).
- Turn roaming ON for your travel eSIM, and OFF for your home SIM — that's the basic rule
- Travel eSIMs are prepaid, so turning roaming on won't trigger automatic high charges
- Be sure to switch your mobile data line over to the travel eSIM, too
- Install before you leave, and activate after you arrive for peace of mind
- Data-only (no phone number, calls, or SMS), but app-based calls like WhatsApp work fine
If you'd like an overview of the whole setup process first, take a look at our eSIM setup guide as well.
The short answer: ON for the eSIM you're using, OFF for your home SIM
Let's start with the answer. To get online with a travel eSIM, you need to turn data roaming ON for that eSIM (line). This isn't a misconfiguration — because a travel eSIM connects by borrowing a local network, your phone treats it as "roaming." Meanwhile, it's best to keep roaming OFF on the SIM you normally use at home, so it doesn't connect unintentionally while you're abroad. "On for the line you use, off for the one you don't" — keep just that in mind and you'll easily avoid double connections and unexpected charges.
What is data roaming, anyway?
Data roaming is the mechanism that lets you get data when you're somewhere your usual carrier's signal doesn't reach (mainly abroad), by borrowing a partner network on the ground. Your home carrier's signal simply doesn't extend to other countries, so roaming is the switch that lets you "borrow the local carrier's signal" instead.
A travel eSIM works on exactly this "borrow a local network" principle. That's why your phone treats it as roaming, and why data roaming needs to be ON for the eSIM (line). If it's off, you can end up in a situation where you have signal but still can't connect — even though the plan is installed correctly. For a lot of people who get stuck during setup, this one setting is the culprit.
Where does the "roaming = expensive" fear come from?
The image of a shocking bill mostly comes from cases where someone used their regular home carrier's SIM abroad with roaming left on. Depending on the plan, an everyday SIM used abroad can switch to pay-as-you-go (charging for each bit of data used), which is how costs quietly pile up. Stories like these have spread, leaving many people with the impression that "roaming is scary."
But that's specifically the story of using your home SIM on metered roaming. A travel eSIM is different: you purchase a plan with a set amount of data and validity period up front, so the whole pricing model works differently. Once you separate the two in your mind, most of the worry fades.
Think of eSIM roaming as "two separate lines"
Most people travel with two lines in their phone: their home SIM and a travel eSIM. Because one device holds two lines, it's easy to lose track of which one you're adjusting — and that's the real source of the confusion. So let's sort out the role of each line.
| Line | Data roaming | Why |
|---|---|---|
| Travel eSIM (destination plan) | ON | It connects by borrowing a local network. If it's off, you may not be able to connect |
| Home SIM (your everyday line) | OFF | To prevent unintended metered roaming abroad. Check calls and SMS reception separately |
Setting it up as "roaming on only for the eSIM you use, off for the home line" makes it easy to avoid double connections and surprise charges. Just as important: switch the line used for mobile data over to your travel eSIM. If you only turn roaming on but leave your home SIM as the "data line," your travel eSIM may not actually get used.
How to set roaming on iPhone
- Open "Settings" → "Cellular" (or "Mobile Data")
- Tap the line you'll use (the name of your travel eSIM plan)
- Turn "Data Roaming" ON
- Go back to the list and, under "Cellular Data," set the data line to your travel eSIM
- For your home SIM, turn "Data Roaming" off — and turn the line itself off if you prefer
On iPhone, giving each line a clear label helps you avoid the "which one is which?" problem once you're abroad. Before you leave, it's a good idea to rename them to something like "Home" and "Travel eSIM."
How to set roaming on Android
- Open "Settings" → "Network & internet" → "SIMs"
- Select your travel eSIM profile
- Turn "Roaming" ON
- Under "Mobile data," switch the line in use to your travel eSIM
- Keep roaming off on your home SIM
* Menu names and locations vary by model and OS version (you may see "Data roaming," "Roaming," or "International roaming," among other labels). You can check whether your device supports eSIM on our eSIM-compatible device checker.
When is the best time to set this up?
"Is it okay to turn roaming on before I leave?" is a common question. For most travel eSIMs, the safest flow is to install the plan before departure and activate (turn on) the line only after you arrive. The idea is to stay on your home SIM while you're still home, then switch to the travel eSIM once you land. Activation timing varies by plan, though, so check the instructions you received at purchase. Getting the installation done before you leave means no scrambling at the airport on arrival. You'll also find the setup logic summarized in our setup guide.
Will turning roaming on lead to a big bill?
Travel eSIMs are generally prepaid plans you use within a set amount of data and validity period. Because of that, turning roaming on for the eSIM doesn't automatically trigger heavy charges beyond what your plan covers. If you use up your data, you can buy more or top up to keep going. Understanding that this is structurally different from the "suddenly a huge metered bill" worry should put your mind at ease. Prices and plan details can vary, so check the current information at the time of purchase.
On the other hand, accidentally leaving your home SIM on while abroad can switch it to metered charging, depending on your plan. Turning roaming off on your home SIM before you depart clears up most of the worry on its own.
A note on data-only plans
Bloomy plans are data-only by design — they don't include a phone number, voice calls over a number, or SMS. If you need voice calls on a number or SMS verification codes, plan ahead with another option: keeping your home number active, or arranging a separate plan that includes a local number. App-based calls such as WhatsApp generally work as long as you have a working data connection. For more on numbers and SMS, our articles on phone numbers and SMS are a helpful reference.
A note when using an unlimited plan
Even with a plan that carries the "unlimited" label, the roaming setup is the same (turn it on for the eSIM you use). Keep in mind, though, that unlimited plans may come with conditions such as a fair-use policy, reduced speeds after a certain amount of use, or limits on tethering. Speed also depends on the local network, the area, and congestion, so it isn't guaranteed to be fast no matter how much you use. Checking the latest terms before you buy is the safest approach. You can see the details on our unlimited plan page. Whether a fixed-data plan or an unlimited one suits you better depends on how you use it — heavy video, versus mainly maps and messaging.
What to do if you've turned roaming on but still can't connect
If you've reviewed your settings and still can't get online, go through the checks below in order. In most cases, one of them does the trick.
- Is the line used for mobile data switched to your travel eSIM?
- Is data roaming turned on for the eSIM?
- Have you arrived at your destination and activated the line? (Activation timing varies by plan)
- Toggle airplane mode on, then off, to re-acquire the signal
- Restart your device
- Set "Network selection" to automatic — or manually reselect the local network once
If that still doesn't fix it, our troubleshooting guide for connection issues has more detailed steps. For more on setup timing and how activation works, see the setup guide as well.
Find and check plans with Bloomy
If you'd like to find a plan that matches your destination, our eSIM comparison page lets you choose by country, data amount, and number of days. You can check the remaining data and QR code for an eSIM you've already purchased from My Account. If you have more questions about setup or usage, our eSIM guide articles and our articles by use case are great places to start.
* Plan contents, pricing, and supported countries may change. Please confirm the latest information shown before you purchase. Connection quality varies depending on the local network, your device, and your location.
