When you use an eSIM abroad, most plans require you to turn on "Data Roaming" for the eSIM tied to your destination plan. The word "roaming" often triggers worries about huge bills, but with a travel eSIM like Bloomy, you use the data within the allowance of the plan you've already purchased—so turning roaming on doesn't automatically trigger expensive overage charges. The key is to handle each line differently: turn roaming ON for the travel eSIM (your destination plan), and turn roaming OFF on your regular home SIM. This guide walks you through the thinking and the steps so you can set things up with confidence.
If you'd like to review the overall setup flow first, take a look at our eSIM setup guide as well.
What is data roaming, anyway?
Data roaming is the mechanism that lets your phone connect to data through a partner's local network when you're outside the coverage area of your usual carrier—mainly when you're abroad. A travel eSIM connects by "borrowing" a local network in exactly this way, so your device treats it as roaming.
In other words, for a travel eSIM to get online, data roaming needs to be turned on for that eSIM (line). If it's switched off, you may end up with no connection even when the plan is installed correctly.
Where does the "roaming = expensive" fear come from?
The image of a shocking bill usually comes from cases where someone kept using their regular home-country SIM abroad and let it roam as-is. That kind of usage can be billed per use (charges added based on how much you use), which is how costs quietly add up. A travel eSIM works differently: you buy a plan with a set data allowance and validity period before you go.
Think about eSIM roaming as "two separate lines"
Many people travel with two lines in their phone: their home SIM and a travel eSIM. This is where confusion creeps in, so let's sort it out line by line.
| Line | Data roaming | Why |
|---|---|---|
| Travel eSIM (destination plan) | On | It connects through a local network. If it's off, you may not get online |
| Home SIM (your everyday line) | Off | To avoid unintended pay-as-you-go data abroad. Check calls and SMS reception separately |
Setting it up so that only the eSIM you're actually using has roaming on, while your home line stays off helps you avoid double connections and unexpected charges. Don't forget to also switch the line used for cellular data over to your travel eSIM.
How to set up roaming on iPhone
- Open "Settings" → "Cellular" (or "Mobile Data")
- Tap the line you'll use (the name of your travel eSIM plan)
- Turn on "Data Roaming"
- Go back to the list and set "Cellular Data" to use your travel eSIM
- For your home SIM, turn off "Data Roaming"—and if you prefer, turn off the line itself
How to set up roaming on Android
- Open "Settings" → "Network & internet" → "SIMs"
- Select your travel eSIM profile
- Turn on "Roaming"
- Switch the line used for "Mobile data" to your travel eSIM
- Keep roaming off on your home SIM
*Menu names and locations can vary depending on your device model and OS version. You can check whether your device supports eSIM on our eSIM-compatible devices page.
Will turning roaming on lead to a big bill?
Travel eSIMs are generally prepaid plans you use within a set data allowance and validity period. Because of this, turning on roaming for the eSIM doesn't automatically rack up large charges beyond the scope of your plan. If you use up your allowance, you can buy more or top up your data to keep going.
By contrast, if you accidentally leave your home SIM on and use it abroad, that line may be billed per use depending on your contract. Turning off roaming on your home SIM before you depart gives you peace of mind.
Keep in mind: these are data-only plans
Bloomy plans are data-only—they don't include a phone number, SMS, or voice calls. If you need voice calls tied to a phone number or SMS-based verification, consider options such as keeping your home number active, or arranging a separate plan that includes a local number. Calling apps like WhatsApp can often be used wherever you have a working data connection.
Things to know when using an unlimited plan
Even for plans labeled "unlimited," the roaming setup is the same. That said, unlimited plans may come with conditions such as a fair use policy, reduced speeds after a certain amount of usage, and whether tethering is allowed. Speed also depends on the local network, the area, and congestion, so "always fast no matter how much you use" isn't guaranteed. It's worth checking the latest terms before you buy. You can find details on our unlimited plans here.
If roaming is on but you still can't connect
If you've reviewed your settings and still can't get online, try checking these points in order:
- Is the active line switched to your travel eSIM?
- Is data roaming turned on for the eSIM?
- Have you arrived at your destination, and is the line activated? (Activation timing varies by plan)
- Toggle airplane mode on and then off to reconnect to the network
- Restart your device
If that still doesn't fix it, our connection troubleshooting guide has more detailed steps. For setup timing and how activation works, see the setup guide too.
Find and manage your plan with Bloomy
If you'd like to find a plan for 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 want to learn more about settings and usage, our eSIM guide article list is a helpful resource.
*Plan contents, pricing, and supported countries are subject to change. Please confirm the latest details shown at the time of purchase.
