In short: an eSIM (embedded SIM) is a connection chip soldered inside your mobile that replaces the physical SIM card: you buy a data plan online, scan a QR code, and within minutes you have internet at your destination, without roaming and without visiting any store upon arrival.
What is an eSIM (embedded SIM)?
If you've ever arrived at an airport and had to wait in line to buy a local SIM card, you perfectly understand the problem that an eSIM solves. The word comes from embedded SIM: a tiny chip soldered to your phone's motherboard that does exactly the same thing as a plastic SIM card, but without being a plastic card.
You don't have to insert it, you don't have to change it, it doesn't get lost, it doesn't bend or scratch. It's activated digitally: you scan a QR code (or install the profile with a link) and your mobile is connected to the corresponding operator's network. If you were looking for "o que é esim" because you saw the term somewhere in Portuguese, this is exactly it: an integrated virtual SIM, with no physical component to handle.
The technology is neither new nor experimental. It was standardized by the GSMA (the association that brings together mobile operators worldwide) and has been present in high-end smartphones since 2018-2019. Today it is the default standard in most phones sold in Europe and the United States, and the mechanism behind any travel eSIM you buy for your next destination.
How does an eSIM work step by step?
The process is simpler than it seems the first time, and doesn't require any technical knowledge:
- Buy the data plan online, ideally before you travel (although you can also do it at your destination if you have WiFi).
- Receive a QR code by email, usually within minutes of purchase.
- Scan the QR from your mobile settings, connected to a WiFi network. The operating system automatically downloads the eSIM profile.
- Activate the data line when you want the plan to start counting (some plans activate automatically when they detect the destination network; others you activate manually).
- Upon landing, your mobile connects to the local network automatically. There's no need to look for a store or fill out any forms at the airport.
The entire process, from start to finish, takes less than five minutes. That's exactly the idea behind landing with internet, without roaming and without stress: you do the work before getting on the plane, not after getting off. If you want the exact installation details for iOS and Android, we have a complete step-by-step installation guide.
eSIM vs. physical SIM: key differences
Functionally, an eSIM and a physical SIM do the same thing: they identify your line to the operator's network so you can use data, and in some cases calls and SMS. The difference is not in what they do, but in how they are managed.
| Aspect | Physical SIM | eSIM |
|---|---|---|
| Installation | Physically insert the card | Scan a QR code |
| Delivery | Store pickup or postal delivery | Email, instantly |
| Loss or theft of mobile | You also lose the card | The profile is linked to the device, not a physical object |
| Change operator at destination | Take out one card, insert another | Change profile from settings, without touching the hardware |
| Dual line (personal number + travel data) | Requires dual physical slot (dual SIM) | Coexists with your physical SIM or another eSIM on the same phone |
| Availability upon arrival | Depends on finding an open store | Already ready before leaving home |
Your physical SIM with your usual number remains active in parallel: you continue to receive calls and SMS while the eSIM handles only data at the destination. It's the combination most travelers use: a personal number for important things, local data without roaming for everything else.
Is the eSIM permanent? Can it be deleted or transferred?
This is one of the most frequently asked questions (are eSIMs permanent, in English) and the short answer is: no, it doesn't have to be. An eSIM profile can be installed, used, and deleted when you no longer need it, just like you would uninstall an app. In the case of travel eSIMs, it's common for the profile to remain on your mobile, occupying space inactive once the plan runs out, and you can manually delete it from settings if you want to free up that digital slot.
What needs to be clear is that an eSIM profile, unlike a physical card, cannot be removed from one mobile and inserted into another. If you change phones, you need to activate a new profile on the new device (some operators allow "transferring" the profile between your own Apple devices, but this is not common for single-use traveler eSIMs). That's why it's advisable to buy the eSIM with the phone you're going to take on your trip already decided, not before.
What exactly is a virtual eSIM?
When we talk about "virtual eSIM" we are referring to the same thing as "eSIM" for short: there is no physical card at any point in the process, the entire profile lives in the embedded chip of the phone. The term "virtual" simply insists on this absence of plastic, and sometimes causes confusion because it seems to suggest something different from the standard eSIM. If you are interested in the technical detail of what difference there is (or isn't) between both terms, we explain it calmly in what is a virtual eSIM.
Is my mobile compatible with eSIM?
Most smartphones launched from 2018-2019 onwards are compatible, but it's a good idea to check before buying any plan. These are the most common ranges by manufacturer:
- iPhone: from iPhone XS (2018). In the United States, from iPhone 14 onwards, the model only comes with eSIM, with no physical slot.
- Samsung Galaxy: from the S20 series in most markets, including S21, S22, S23, S24, and the Z Fold and Z Flip foldables.
- Google Pixel: from Pixel 3 (2018).
- Motorola, Oppo, Xiaomi and other Android: selected models, especially mid-to-high range from 2020-2021 onwards.
To confirm it on your own device: on iOS go to Settings → General → About and look for "eSIM availability"; on Android, usually in Settings → Connections → SIM Manager (the exact menu varies by brand). A detail that almost no one checks: some mobiles sold in specific markets —mainland China is the most common case— have the eSIM hardware factory-locked even if the same model in other countries does allow it. If you bought the phone outside Europe or the United States, it's worth checking before assuming it's compatible.
How many eSIMs can I have active at the same time?
It depends on the device, but most modern smartphones allow you to store several eSIM profiles (usually between 5 and 10), although they can only have one or two active simultaneously for data. In practice, this means you can save the eSIM from your last trip to Italy and activate the one for your next trip to Japan today, without deleting anything, and choose which one uses data at any given time from the line settings.
It is common when traveling to have your physical SIM (with your personal number, for calls and SMS) and the destination's data eSIM active at the same time. This way you avoid roaming from your home operator without losing the ability to receive calls or texts on your usual number.
Is eSIM secure?
Yes. eSIM uses the same security and encryption standards as physical SIM cards—the same authentication protocol with the operator's network—with the added advantage that the profile is downloaded directly and encrypted from the operator's server, without passing through any physical intermediary that could be lost or cloned. Since there is no physical object, there is also no risk of someone extracting it from your phone if it is stolen: the profile is linked to the device's hardware.
Common mistakes and what almost no one tells you about eSIM
There are a series of details that do not usually appear in the basic explanations of how an eSIM works and that avoid many headaches during the trip:
- Install it before leaving home, not at the destination airport. You need WiFi to download the profile, and the WiFi at the arrival airport is not always reliable or fast. Do it calmly from your usual WiFi, days in advance.
- Do not delete the profile until you confirm that the line works. Some Android phones allow you to "reinstall" an already scanned QR if something goes wrong, but many do not. If you have doubts about whether it was activated correctly, do not delete the profile as a first step in troubleshooting.
- The same QR code can usually only be scanned once. If you scan it on a device by mistake, you will not be able to reuse it on another without contacting support. Double-check which mobile you install it on.
- "Dual SIM" does not always mean two active data lines at the same time. Many mobiles with DSDS (Dual SIM Dual Standby) can only use mobile data on one line at a time, even if both receive calls. If you need uninterrupted data on both lines, check your model's specifications.
- Not all travel eSIMs include a phone number or allow calls or SMS. Most tourist eSIMs are data-only, by design: it's what you really need to use maps, messaging and networks without roaming, and that's why they are usually more affordable than a plan with voice included.
- Some operators allow you to top up the same plan and others don't. Before assuming you can extend days or data on the fly, check if your specific eSIM allows it; if not, you will have to buy a new plan.
- Your usual operator's roaming and the data eSIM are not accidentally exclusive. If you don't deactivate mobile data on your physical line when you arrive at your destination, your home operator may continue to charge roaming in the background even if you have the eSIM active. Deactivate the physical SIM's data and leave only the eSIM as the data line.
eSIM, roaming, and international physical chip: which to choose?
The eSIM is not the only alternative to your usual operator's roaming, although it is usually the most convenient. Your home company's roaming automatically activates data without you doing anything, but the daily cost can exceed several euros depending on the destination and operator —it is advisable to check the current rate with your company before traveling—. An international physical chip purchased at the destination, for its part, requires finding a store, usually requires documentation, and implies temporarily losing your number while the physical SIM is inserted.
If you want to compare these three options in detail, we have two dedicated guides: what data roaming is and how it works, and the direct comparison eSIM vs roaming, plus international chip vs eSIM if you are still undecided between a physical and a digital card.
How to choose your first travel eSIM
If this is your first time using an eSIM, the easiest way to start is with a specific destination and duration: you don't need a global plan if you're going to be in one country for ten days. Think about how many gigabytes you actually use—maps, messaging, and occasional browsing consume much less than people think—and choose a plan that suits that, not the maximum available. If you want to make the most of the data you buy, this list of tips for saving data with your travel eSIM can save you from buying more than you need.
At PuraSim you can start with specific destinations like the eSIM for Europe or the eSIM for the United States, with a fixed price for the contracted data: no surprises when you return, no small print, and with Spanish support if you have any questions during installation or your trip.
Frequently asked questions about eSIM
What is an embedded SIM?
It's the full technical name for the eSIM: a chip soldered inside the mobile that replaces the physical SIM card and is activated digitally, by scanning a QR code or installing a profile sent by the operator. "Embedded" refers to the chip being part of the phone's hardware itself.
What is the difference between eSIM and e-SIM?
None: they are the same technology spelled in two different ways. "eSIM" is the official spelling used by the GSMA, but it is very common to find it written as "e-SIM" or simply "e sim" in searches and articles.
Is the eSIM permanent or can it be deleted?
It is not permanent: you can delete an eSIM profile from your mobile settings at any time, just as you would uninstall an application. What is not possible is to extract that profile from one device and physically insert it into another, as you would with a traditional SIM card.
Can I use an eSIM in any country?
It depends on the plan you choose, not on the technology itself. Single-country plans cover only that destination; regional or multi-country plans allow you to use the same data in several countries without buying a different eSIM for each one.
Does the eSIM expire if I don't use it?
Yes, each plan has a fixed duration from activation (usually 7, 15, or 30 days). If you buy the eSIM but do not activate it, no days are usually deducted from the plan until you connect it to the destination network.
Do I need an unlocked phone to use an eSIM?
Yes, if your phone is locked to a single operator, you may not be able to install eSIM profiles from other companies even if the hardware is compatible. Check with your current operator if your line is unlocked before buying a travel eSIM.
What happens if my travel eSIM runs out of data early?
It depends on the operator: some allow you to top up the same plan with more data or more days without reinstalling anything; others require you to buy a new plan and scan a different QR. It's advisable to check this before traveling if you know you're going to need more leeway than usual.
