In short: Yes, you need an unlocked phone to use a travel eSIM, but that's not all: the device must also be eSIM-compatible. These are two independent requirements. Check them in one minute with another company's SIM and the code *#06#, and you'll have internet from the first minute you land.
Do I need an unlocked phone for a travel eSIM?
Yes, and it's the right question that almost everyone asks right before buying an eSIM. To use an eSIM on an unlocked phone, you need to meet two conditions simultaneously: the device must not be locked to any carrier, and the hardware must include the eSIM chip. If you miss either of these, the profile will not activate, no matter how well you complete the rest of the process.
This catches many people by surprise because it stems from a false assumption: they think that if the phone is "modern," it will work. And that's not always the case. A brand-new iPhone bought with a two-year contract can still be locked to its carrier, and an eight-year-old unlocked phone might not have an eSIM. Let's break down the confusion between these two concepts, because once you understand it, checking takes literally sixty seconds.
Unlocked and eSIM-compatible: two separate checkboxes
This is where most people get confused, so let's go slow. An unlocked phone accepts any company's SIM card (physical or virtual) without restrictions imposed by the manufacturer or the carrier that sold it. An eSIM-compatible phone is one whose hardware includes the programmable chip necessary to download and activate digital profiles, replacing or complementing the traditional physical SIM. If you want to understand exactly what that chip is and how it differs from a traditional SIM, we have an in-depth explanation in what an eSIM is.
These are requirements that are independent of each other. You can have an eSIM-compatible phone that is locked, and it will be useless. And you can have a completely unlocked phone but no eSIM chip, and there's nothing to install. You need both boxes checked simultaneously. The confusion often comes from assuming that "unlocked" automatically means "modern" and, therefore, "compatible." This is not the case: there are entry-level unlocked phones still sold today without eSIM, and perfectly unlocked phones from more than seven years ago that never had it because the standard didn't exist yet.
In Spain, the good news is that most devices bought outright, without carrier financing, come factory unlocked from day one. Locking almost always occurs when the phone is paid for in installments along with a plan, which is very common with large companies. If that's your situation, don't take anything for granted: check the status before relying on your phone for your trip, not the day before you leave.
How to tell if your phone is unlocked
Checking if a phone is unlocked doesn't require special tools or technical knowledge. You have three ways, from the quickest to the most reliable:
- Try with another physical SIM: Borrow a card from a different company than yours (from a friend, family member, or even an old pre-paid SIM) and insert it into your phone. If it detects coverage and you can make calls, the device is unlocked.
- Check your phone settings: On some Androids, a "network lock" or "SIM not allowed" message appears when inserting a foreign card. On iPhone, go to Settings > General > About and look for the "Carrier Lock" section; if it says "No SIM restrictions," you're unlocked.
- Ask your carrier directly: If you bought the phone financed, the company can confirm the exact status and, if you've finished paying for it, unlock it on the spot.
Little-known trick: In Spain, a phone bought separately at a general store, on Amazon, or second-hand almost always comes factory unlocked. Locking mainly occurs when the device is financed along with a line from a specific carrier.
If you still have doubts after these tests, calling your carrier is the safest way: they are required by regulation to inform you of the locking status of any device associated with your contract.
How to tell if your phone is eSIM-compatible
Once you've confirmed your phone is unlocked, it's time for the second check: whether the hardware supports eSIM. Here are the most direct methods:
- Dial *#06# on your phone's dial pad, as if you were making a call. If your phone is compatible, you'll see an EID number next to the IMEI. If no EID appears, the device does not have an eSIM chip.
- Look for "Add eSIM" or "Add data plan" within your mobile network or mobile data settings. If that option exists in your menu, the phone supports it.
- Check the model directly: As a general reference, iPhones from XS/XR onwards, Samsung Galaxy from the S20 series, recent generation Google Pixels, and a good portion of current mid-to-high-end Xiaomi and Motorola phones already incorporate it. Models prior to 2018 generally do not.
Keep in mind that some phones sold outside the European Union, especially in Asian markets, come with eSIM hardware but with the function deactivated by software depending on the sales region. This is a nuance that almost no one mentions and that can give you a false negative if you bought the device through import.
What happens if your phone is locked by the carrier
If after checking you discover that your phone is locked, the eSIM will not connect, no matter how compatible the hardware is: the system itself will reject any profile that is not from the company to which it is tied. The solution is to unlock it, and in Spain it is a recognized right: when you finish paying for a financed device, your operator is obliged to unlock it, usually free of charge.
The process varies by company, but it is usually resolved by phone, through the app or in a physical store, with a deadline ranging from a few hours to a couple of days. Meanwhile, avoid buying the eSIM "just in case": it is more orderly to unlock the device first and then purchase the plan, so on the day of the trip you don't depend on the process being resolved in time. A nuance that many guides overlook: an imported phone bought outside the European Union may be locked to a specific market (for example, it only works with operators in that country), something different from financing lock, and should be checked separately before relying on it for travel. Once unlocked, the rest of the process is identical to that of any unlocked phone, and activating the data profile takes barely a minute.
Summary table: unlocked, compatible, and locked
To avoid mixing concepts, this table summarizes what each status means, how to check it, and what it implies for your travel eSIM:
| Phone Status | What it means | How to check it | Can you use an eSIM? |
|---|---|---|---|
| Unlocked and compatible | No carrier lock + eSIM chip in hardware | Another SIM works + *#06# shows EID | Yes, without any problem |
| Compatible but locked | Has eSIM chip, but tied to a carrier | *#06# shows EID, but another SIM gets no coverage | No, until unlocked |
| Unlocked but no eSIM | Accepts any carrier, but no eSIM chip | Another SIM works, but *#06# does not show EID | No, hardware does not allow it |
| Locked and no eSIM | Does not meet either requirement | Neither test is passed | No, you would need another device |
How to install an eSIM on an unlocked phone, step by step
With your unlocked and compatible phone confirmed, activating your travel eSIM is one of the easiest things you'll do before leaving home. The general process is as follows:
- Choose the plan for your destination country or region, whether for Spain if you're coming from abroad, for several European countries on the same trip, or for the United States, and you'll receive the QR code by email after purchase.
- Still at home and connected to Wi-Fi, go to Settings > Mobile Data (or Mobile Network) > Add eSIM, and scan the QR code you received.
- Name the line, for example "Travel," and leave your Spanish line active as primary for calls and SMS.
- As soon as you land, activate the eSIM data line, and that's it: internet working from the moment you leave the terminal, without looking for airport Wi-Fi or activating your carrier's roaming.
If you prefer the complete details of the process, with screenshots and specific cases depending on the manufacturer, you can find the specific guide on how to install an eSIM.
eSIM vs. roaming with your Spanish carrier
A common question that arises right after figuring out the unlocked phone situation is whether it's really worth switching systems. Data roaming with your Spanish carrier, colloquially known as roaming, still exists and still has different conditions depending on the destination: within the European Union it is usually included in your regular plan, but outside of it the cost can skyrocket and exceed several euros per day if you don't contract a specific bundle. We explain this in more detail in our guide on what data roaming is.
The travel eSIM, on the other hand, works with a local or regional data plan that you contract before you leave, designed specifically for tourists, and does not depend on what your usual carrier charges you outside of Spain. If you want to compare both options point by point, with their advantages and disadvantages depending on the type of trip, we have a complete analysis in eSIM vs. roaming. In any case, for the eSIM to be a real option, the initial requirement remains the same as discussed in this guide: an unlocked and compatible phone.
Common mistakes and what almost no one tells you
Beyond the obvious, there are a number of details that are only discovered when you've already had a problem with an eSIM, so it's better to anticipate them:
- Confusing EID with IMEI: These are distinct numbers that appear together when dialing *#06#. The IMEI identifies the device; the EID specifically identifies the eSIM chip. If your carrier asks for the EID to unlock or manage a line, don't give them the IMEI by mistake; you'll waste time.
- Company phones with MDM management: If your phone is managed by your company's IT department, it's common for the option to add an eSIM to be restricted by policy, even if the hardware is compatible and the phone is unlocked. Check this in advance if it's your only device for the trip.
- Second-hand phones are not always "clean": An unlocked device may still have an IMEI reported as stolen or lost by its previous owner in another country. This doesn't directly block the eSIM, but it can cause coverage problems with some carriers. If buying second-hand, check the IMEI history before traveling.
- Not all "dual SIM" phones are the same: Some models, especially versions sold in certain markets, offer a double physical slot instead of physical plus eSIM. Before assuming your phone supports dual mode with eSIM, confirm it by the exact model and not just by the generic "dual SIM" label on the box.
- Installing the eSIM at the airport, without Wi-Fi, almost never goes well: The profile download process requires a stable internet connection. Always do it at home, with Wi-Fi, and activate it only upon landing. This is the most repeated and easiest mistake to avoid.
If you also want to maximize your plan's data during your trip, without running out of megabytes halfway through your stay, take a look at our tricks to save data with your eSIM.
Frequently Asked Questions
Can I use an eSIM if my phone is locked by the carrier?
No. A locked phone rejects any profile that is not from its carrier, so the travel eSIM will not connect even if the hardware is compatible. First, you need to unlock the device, which your carrier must do free of charge once you finish paying for it.
How do I know if my phone is both unlocked and compatible?
These are two independent checks. For the lock, insert a SIM from another company or check it in Settings. For compatibility, dial *#06# and look for an EID number next to the IMEI. If both conditions are met, your phone is ready for a travel eSIM.
Is an unlocked phone always eSIM-compatible?
Not necessarily, and it's one of the most common misunderstandings. An unlocked phone only indicates that it accepts any carrier. eSIM compatibility depends on the hardware: models prior to 2018 and a good portion of current entry-level phones do not incorporate it, even if they are completely unlocked.
Does unlocking a phone cost money in Spain?
Generally not. When you finish paying for a financed device, your carrier is obligated to unlock it, usually free of charge. The process can take from a few hours to a couple of days depending on the company, so it's advisable to request it well in advance of your trip.
Can I have both my travel eSIM and my Spanish SIM active at the same time?
Yes. eSIM-compatible phones work in dual mode: you keep your Spanish card for calls and SMS and use the travel eSIM only for data. This way you keep your usual number while browsing with the local rate of your destination.
How do I distinguish the EID from the IMEI when dialing *#06#?
When you dial that code, you will see several numbers. The IMEI identifies the physical device and is usually displayed first; the EID, which is longer, identifies the eSIM chip and only appears if the phone is compatible. If you don't see an EID at all, the hardware does not support eSIM.
What if I bought my phone imported from outside the European Union?
It may have the eSIM chip physically present but with the function limited to its market of origin by software, or be locked to a specific operator in that country. It is advisable to check this with the two tests in this guide before assuming that it will work for your trip.
Conclusion
To use a travel eSIM, you need an unlocked phone that is also eSIM-compatible: these are two distinct requirements, and checking them takes less than a minute with another company's SIM and the code *#06#. If your device meets both conditions, you can forget about expensive roaming and searching for Wi-Fi when you arrive. Check your phone, choose your destination, and activate the profile before leaving home to land with internet, no roaming, and no stress. Discover all the PuraSim plans available for your next trip.
