If your device supports dual eSIM, you can register two eSIMs at the same time and switch between them—no physical SIM required. In short, the setup comes down to three steps: "① check that your device is compatible → ② add your first and second eSIM in order → ③ choose which line handles mobile data (your default)." You can store more than one line, but on most phones only one line can be used for data at a time, so the key is deciding which line you actually connect through. This guide walks you through the setup and how to pick the right line, in plain terms even if it's your first time.
- Dual eSIM in three steps: ① check compatibility ② add two eSIMs ③ choose your data line
- Even with two eSIMs stored, typically only one can use data at a time
- For travel, set your local/travel eSIM as the mobile data line
- Data-only eSIMs can't make number-based calls or send SMS, but app calls (e.g. WhatsApp) usually work
- If you can't connect, first check whether you've selected the right data line
If you'd like to get a feel for the overall setup process first, take a look at our complete eSIM setup guide for travel as well.
What is dual eSIM? How using two eSIMs works
Dual eSIM is a feature that lets you register two eSIMs (the kind written directly to your device) on a single phone. Unlike the common "eSIM + physical SIM" combination, here we focus on running two eSIMs with no physical SIM at all.
With two lines stored, you can carry, for example, an "everyday line" and a "travel line" on one phone and switch as needed. Since there's no SIM to swap in and out, you won't be scrambling to change cards when you arrive at your destination.
"Storing two lines" and "using two lines at once" are not the same
This is an easy point to trip over. Registering (saving) multiple eSIMs is a different matter from using them for data at the same time. On many devices, only one line can be used for data at a time, while the other stays on standby or ready to switch. Exactly how simultaneous standby behaves depends on the model and OS version, so check the specifications for your particular device.
First, check: is your device dual-eSIM compatible?
Before you start, confirm that your phone can register two eSIMs. Even within the same series, support can vary by release date and model.
- iPhone: Many newer models can store multiple eSIMs and have two lines active (though typically only one can use data at a time).
- Android: Support varies widely by manufacturer and model. Check whether your settings menu includes a "SIM manager" or "Mobile network" option.
You can look up how to check compatibility and see representative models on our eSIM-compatible devices page. Confirming compatibility before you buy gives you peace of mind (support reflects general trends as of June 2026; for the latest details, please check each manufacturer's official information).
How to add two eSIMs
The basic flow is "add the first eSIM → add the second → give each line an easy-to-recognize name." Here we'll show the general steps using iPhone as an example (screen names may differ slightly by model and OS).
Add your first eSIM
- Open "Settings" → "Cellular" (Mobile Data)
- Choose "Add eSIM" or "Add Cellular Plan"
- Scan the QR code issued at purchase (or enter the details manually)
- Follow the prompts to finish installation
Add your second eSIM
Repeat the same steps to add your second eSIM. Afterward, giving each line a clear label such as "Main" or "Travel" makes it much easier to switch later without confusion.
You can turn off lines you're not using
Even with two lines stored, you can put a line you won't use for now on standby with the "Turn this line on/off" toggle. A simple approach is to turn your travel line on only after you arrive, which also helps you avoid unwanted data use. If you get stuck on the overall setup, our setup guide page is a helpful reference.
Which line connects? How to choose your default line
Once both lines are stored, choose which line to use for "Mobile Data". This is the heart of switching between lines.
| Setting | What it does | How to choose |
|---|---|---|
| Mobile Data | The line used for internet | Your travel/local line when abroad; your everyday line at home |
| Default Voice Line (varies by device) | The main line for calls and SMS | Set this if you have a line with a phone number |
| Allow Mobile Data Switching | Automatically switches to the other line when out of coverage | Turn off if you want to avoid unintended data use |
When traveling, the basic setup is to set "Mobile Data = your travel/local eSIM." If you turn on "Allow Mobile Data Switching," the other line may be used when one is out of coverage. If you want to avoid connecting on an unintended line, leaving this off is the safer choice.
Important notes when using a data-only eSIM
Bloomy plans are generally data-only. Even when running two eSIMs with dual eSIM, a data-only eSIM generally cannot make calls or send/receive SMS using a phone number. Keep the following in mind.
- If you need a phone number, SMS, or voice calls, please also look into a line that includes a number or another option.
- App-based calls such as WhatsApp may work as long as you have a working data connection.
- Services that require SMS verification may not be receivable with a data-only eSIM alone. Since keeping a number and receiving SMS are important, always check the latest information for each service.
If you're considering "one line with a number, the other for data," understanding how data-only eSIMs work will help you combine them with fewer surprises. For more on numbers and SMS, see our phone number & SMS category articles as well.
What to check when you can't connect
When running two lines and "the internet won't connect," the cause is often the wrong line selection. Try checking in this order.
- Is your Mobile Data line set to the eSIM you want to use?
- Is the line you want turned on (not left on standby)?
- Is data roaming turned on for your travel eSIM (follow your plan's instructions)?
- Does your plan require an APN (connection settings) to be configured?
- Try toggling Airplane Mode on/off or restarting your device
If that still doesn't fix it, our troubleshooting page covers solutions by situation.
Choosing a Bloomy plan for dual eSIM use
With Bloomy, you can find plans by destination, data amount, and number of days. For dual eSIM use, it's easy to keep your first line for everyday use and add a second line for each trip, switching with no SIM swapping. You can check your purchased eSIMs, remaining data, and QR codes anytime in My Account.
If you're unsure which data amount to choose, our eSIM comparison page lets you compare by country, data, and days side by side. For long stays or when your usage is hard to predict, one option is to consider a large-capacity or unlimited-type plan after reviewing the terms (unlimited-type plans may apply a fair use policy, speed limits after a certain amount of use, or tethering conditions, so please check the latest terms before purchasing; actual connection quality varies with the local network, your device, and your area).
Summary: Switch between two lines and travel light, every day
On a compatible device, dual eSIM can be set up with the flow "① check compatibility → ② add two eSIMs → ③ choose your data line." What matters most is being mindful of which line you connect through, and understanding that a data-only eSIM generally can't be used for a phone number or SMS. Start by checking device compatibility, and once your destination is set, pick a plan on the comparison page.
