Last updated: July 30, 2026 (details are subject to change)
As a trip gets closer, it is easy to stall on questions like "Should I do anything about my mobile plan back home?" or "Once I land, what exactly do I switch on to get online?" The short answer: leave your home-country plan exactly as it is — no cancelling, no switching — and let a travel eSIM handle only the data you use abroad. That setup is called "dual SIM," and it lets a single phone cover both roles without any fuss.
This article walks through what to take care of before you leave, what to turn on after you land, and how to put everything back when you return, in that order. Adding the eSIM is a single tap on a setup link, so the flow is easy to follow even if phone settings are not your thing.
- You can keep your home-country line active
- Add the eSIM with one tap before you leave
- Switch your data line to the travel eSIM once you arrive
- Switch it back when you get home
The short version: keep your home line, switch only data to the travel eSIM
There are really only two things to do before you travel. Leave your home-country line where it is, add a travel eSIM, and then set the travel eSIM as the line used for data once you arrive. There is no need to suspend or cancel your existing plan.
Set it up this way and coming home is simply a matter of switching back. For a wider look at how to think about your phone abroad when you already have a plan at home, see Using your phone overseas when you have a plan back home: a beginner-friendly guide. Reading both makes the pre-departure decisions easier.
Keep in mind that whatever international service your home operator offers — roaming options, daily rates, add-ons — can change over time. Check your own contract on your operator's website or in your account page for the current terms (as of July 2026).
What is dual SIM? Two lines, one phone, different jobs
Dual SIM simply means keeping two lines on one phone and using each for a different job. Most eSIM-capable phones let you keep your existing home line in place and add an eSIM alongside it as a second line.
It helps to think of the division of labor like this while you're travelling.
| Line | Main job | While you're abroad |
|---|---|---|
| Your home-country line | Holds your phone number | Leave it in place. Turn off its mobile data and roaming if you want to avoid unintended usage |
| Travel eSIM (Bloomy) | Data while you're abroad | Turn it on after you arrive and set it as the line used for data |
"Number stays home, data goes local" is the mental model — hold on to that and the settings screens stop being confusing.
Three things to sort out before departure
1. Check that your phone supports eSIM
First, confirm that your phone supports eSIM and is not carrier-locked. Skipping this check is the most common reason people end up scrambling on the day of the flight. If you're unsure, look up your model on the eSIM compatible devices page.
2. Pick a plan that matches your destination, trip length, and data needs
Next, choose a plan based on where you're going, how long you'll be there, and how much data you expect to use. If you're mostly using maps, looking up restaurants, and scrolling social feeds, a large allowance often isn't necessary; if you plan on watching a lot of video, give yourself some headroom. Plans, supported countries, and pricing can change, so check the current details on the eSIM comparison page as you choose, and confirm the price at the time of purchase.
3. Tap the setup link somewhere with a stable connection
After purchase, tap the setup link you receive while you're on a stable connection — home Wi-Fi is ideal — and add the eSIM to your phone. Getting the install done before you leave, so that all you have to do on arrival is switch the line on, takes a lot of pressure off the moment you land. Step-by-step instructions are in the setup guide.
The steps: before departure, after arrival, and after you're back
Before departure (while you're still home)
- On a stable connection such as Wi-Fi, tap the setup link you received.
- Follow the on-screen prompts to add the eSIM as a line.
- Give the new line an easy label, such as "Travel."
- At this stage it's fine to leave the new line switched off (activation timing varies by plan, so check the instructions that came with your purchase).
Once you arrive
- Open your phone's cellular settings and switch on the travel eSIM.
- Set the travel eSIM as the line used for mobile data.
- If you want to avoid unintended usage, turn off mobile data on your home-country line.
- Toggle airplane mode on and off once, then check the signal indicator.
After you get home
- Set your home-country line back as the line used for mobile data.
- Switch the travel eSIM off (you can delete it if you no longer need it).
- If you turned off mobile data on your home line, turn it back on.
The exact wording of these settings varies a little between phones and OS versions. If you can't find something, searching your settings app for "cellular" or "SIM" is usually the fastest route.
Data roaming: the part that trips people up
This is where most people get stuck, so treat the two lines separately. The trick is to be clear, every time, about which line you're looking at.
On the travel eSIM side, depending on the plan and the local network it connects to, you may be told to switch data roaming on. If so, follow the instructions provided with your purchase. On your home-country line, meanwhile, turning both mobile data and data roaming off keeps unintended usage from happening while you're away.
How much you switch off on your home line affects whether you can still receive calls and texts on that number. Whether incoming calls and SMS work abroad — and what they cost — depends on your contract, so if you're expecting anyone to reach you on that number, check your operator's official information before you leave.
What a data-only eSIM can and can't do
Bloomy eSIMs are data-only. Knowing this up front avoids the "this isn't what I expected" moment after you land.
| What you want to do | On a data-only eSIM |
|---|---|
| Maps, search, social media, email | Works as usual over mobile data |
| Calls in WhatsApp, Messenger, FaceTime and similar apps | These run over data, so they work as usual |
| Voice calls to and from your phone number | Not available on a data-only eSIM |
| SMS to and from your phone number | Not available on a data-only eSIM |
In other words, the only things you lose are voice calls and SMS tied to a phone number — app-based calling works just like it does at home. If you do need number-based calls or texts, keep your home-country line in place, or look at other options such as a plan that includes a number or a local SIM.
Speed and stability also vary with the local network, your device, the area you're in, and how busy the network is at the time. Plans are subject to a fair use policy, so heavy usage may be managed accordingly — check the details of your plan at the time of purchase. Coverage can feel patchy right after landing or in crowded places like large stations and airports, so give yourself a little time to get set up rather than doing it in a rush.
Who this setup suits — and who it doesn't
Dual SIM is convenient, but it isn't the right answer for everyone. It's worth working out which side you fall on before you buy.
A good fit if you…
- Want to keep your home-country phone number as it is
- Mostly use data while travelling and can stay in touch through apps like WhatsApp
- Want to travel light with just your phone (no picking up and returning a pocket Wi-Fi router)
- Are taking a short trip or business trip and only need connectivity for a set number of days
Consider other options if you…
- Have a phone that doesn't support eSIM
- Expect to use number-based calls or SMS regularly while abroad
- Need to share one connection across several people or devices (tethering terms vary by plan)
- Are staying long term and want a local number for everyday life
If you can't get online: what to check, in order
When something isn't working abroad, going through these in order is faster than poking at whatever comes to mind.
- Is the travel eSIM line switched on?
- Is the travel eSIM set as the line used for mobile data?
- Have you set data roaming as instructed?
- Have you toggled airplane mode off and on, or restarted the phone?
- Has your plan's start date and validity period actually begun?
If none of that helps, the troubleshooting page covers what to check in specific situations. Questions about buying and setup are answered on the FAQ page.
In short: when in doubt, start with "keep the home line"
If you already have a mobile plan at home, the first step for any trip is simply deciding: the home line stays. From there, hand data over to a travel eSIM while you're away, and switch back when you return. Once that flow is clear, the pre-departure to-do list gets short very quickly.
If you already know where you're headed, the eSIM comparison page lets you search plans by country, data allowance, and number of days. If you'd like to go over the setup steps once more, the setup guide is there too.
* This article reflects information as of July 2026. Plan contents, supported countries, and terms of use are subject to change, so please check the current details before purchasing. Bloomy eSIMs are data-only: no phone number, no SMS, no voice calls, and usage is subject to a fair use policy. Network speed and stability vary by local network, device, and location. For what your own operator offers abroad and what it charges, check that operator's official information.
