Your iPhone is perfect for traveling with eSIM: it can have your Spanish card as the main line and, at the same time, a data eSIM from the country you are traveling to as a secondary line. This way, you keep your number for calls and WhatsApp while browsing with cheap local data, without roaming. In this guide, I explain, step by step, how to set up your iPhone so that each line does what it needs to do during your trip.
How iPhone Dual SIM works
The iPhone allows you to have two active lines at once: your Spanish card (physical or eSIM) and a travel eSIM. In Settings, you can choose which line uses mobile data, which manages calls, and from which you send each message. That flexibility is exactly what you need when traveling.
The idea is simple: you leave your Spanish line as "Primary" so that you continue to receive calls, bank SMS, and verification codes on your usual number, and you set the destination eSIM as the "Data" line. You browse cheaply with a local network, but you remain reachable. Modern iPhones even support two installed eSIMs and several saved ones, which is useful if you travel a lot; you can see the details in the guide on how many eSIMs an iPhone can have. If you want to understand dual mode in depth, you have the guide on how dual SIM works with eSIM.
Which iPhones are eSIM compatible
Almost all iPhones from iPhone XR and XS (2018) onwards support eSIM, including the entire 11, 12, 13, 14, 15 range and later models. If your iPhone is from recent years, you can assume that it works with eSIM for travel.
To check it yourself, go to Settings, then Mobile Data, and look for the "Add eSIM" or "Add Data Plan" option. If it appears, your iPhone is compatible. Keep in mind an important nuance: the iPhone must be unlocked by the carrier, meaning not locked to a specific company, to be able to use an eSIM from another provider. Most iPhones bought in free stores or already paid for are. The latest models have their own detailed guide in eSIM on iPhone 15 and 16, with the particularities of each one.
Quick check: dial *#06# on the phone keypad. If an EID appears among the codes, your iPhone has an eSIM chip and is compatible. It's the most direct way to clear up any doubts before buying the plan.
Install the travel eSIM step-by-step
Installing the eSIM on the iPhone takes about a minute and is done at home with Wi-Fi, before flying. You receive a QR by email when you purchase the plan, and you just have to scan it from Settings. These are the exact steps.
- With Wi-Fi, open Settings and go to Mobile Data.
- Tap "Add eSIM" and then "Use QR Code".
- Scan the QR you received by email when you purchased the eSIM.
- When the iPhone asks you to label the lines, name the eSIM "Travel" or "Data" and your card "Main".
- Don't delete anything: the two lines coexist without problems.
If the QR doesn't scan the first time, you can enter the data manually with the code that also comes in the email. The complete guide with screenshots is in eSIM installation and activation on iPhone, and if you prefer the generic process for any mobile, in how to activate an eSIM.
Configure main and data line
Once the eSIM is installed, you have to tell the iPhone what each line does. This is where many people make mistakes and end up spending on roaming unintentionally. The correct configuration for traveling is this table.
| iPhone Setting | What to choose for travel | Why |
|---|---|---|
| Mobile Data | Travel eSIM | You browse with a cheap local network at your destination |
| Default Voice Line | Your Spanish SIM | You receive calls and SMS on your usual number |
| Mobile Data Switching | Deactivated | Prevents the iPhone from using your Spanish SIM for data and charging you for roaming |
| Data Roaming for Spanish SIM | Deactivated | Extra protection against roaming charges |
With these four settings, you always browse via the eSIM and never via your Spanish plan, while still receiving calls on your number. It's the combination that avoids surprise bills.
Settings you should adjust before flying
Before getting on the plane, it's a good idea to get everything ready at home with Wi-Fi, so that when you land, you just have to turn on your phone. Review this quick list so you don't forget anything important about your iPhone.
- Install the eSIM and label the lines as "Travel" and "Main".
- In Mobile Data, set the travel eSIM as the data line.
- Deactivate "Mobile Data Switching" so that it doesn't jump to your Spanish SIM.
- Deactivate data roaming for your Spanish card.
- Check that WhatsApp is still linked to your Spanish number (it doesn't change on its own).
If you want your WhatsApp and calls to keep your usual number while browsing with the eSIM, you can find the details in the guide on using eSIM while keeping the same number. With everything ready, when you land, you just activate eSIM data usage and you're connected.
Common problems and how to solve them
Most issues with eSIM on iPhone are due to a misplaced setting, not a plan failure. These are the most common travel mishaps and their quick solutions.
- No data upon arrival: check that the eSIM is set as the data line and that eSIM data roaming is activated.
- I'm still being charged roaming: you had "Mobile Data Switching" or Spanish SIM roaming active; deactivate them.
- QR not scanning: enter the data manually using the code from the email.
- WhatsApp not sending: check that the eSIM has data and coverage, and that WhatsApp uses mobile data.
If you change iPhones during or before your trip, don't lose your eSIM: see how to transfer an eSIM to a new phone to take it with you without buying a new plan.
Frequently asked questions
Can I use a travel eSIM without removing my Spanish SIM from my iPhone?
Yes, that's the whole point. The iPhone supports two active lines at once: you leave your Spanish SIM as the main line for calls and SMS, and the travel eSIM as the data line. You browse with a cheap local network without losing your number or your usual card.
How do I know if my iPhone is eSIM compatible?
Almost all iPhones from the XR and XS (2018) are. To confirm, dial *#06# and check if an EID appears; if it does, your iPhone has an eSIM chip. You can also go to Settings, Mobile Data, and see if the "Add eSIM" option appears. The iPhone must be carrier unlocked.
Why am I still being charged roaming if I have the eSIM installed?
This is almost always due to the "Mobile Data Switching" setting being active, which allows the iPhone to use your Spanish SIM if the eSIM temporarily loses signal. Deactivate it and also deactivate data roaming on your Spanish card. This way, the iPhone will only use the eSIM for browsing.
Can I still use WhatsApp with my Spanish number?
Yes. WhatsApp remains linked to your Spanish number and works with the eSIM's data without needing to re-register. It doesn't change automatically when you install the eSIM. Just make sure WhatsApp has permission to use mobile data and that the eSIM has coverage at your destination.
Do I need to install the eSIM before flying or when I arrive?
Install it at home with Wi-Fi, as it takes about 1 minute and needs a connection to download the profile. Then, when you land, you just activate the eSIM's data usage. Leaving it for the destination airport without Wi-Fi is the most common and avoidable mistake.
Conclusion
The iPhone is made for traveling with an eSIM: two lines, your Spanish number intact, and cheap local data by simply choosing which line does what. Install it at home, set the data to the eSIM, and deactivate roaming on your card. With this setup, you'll land connected and without any unpleasant surprises on your bill, no matter where you travel.
