What is a nano SIM?
A nano SIM is the smallest physical chip in the SIM family: a card that you insert into your phone's tray to connect to a carrier's network. Most phones have used it since 2012, and it's different from an eSIM, which isn't a card but a digital profile installed on the device.
Before the nano SIM, there were two other sizes: the standard SIM (the largest, used until the mid-2000s) and the micro SIM (an intermediate step). All three types contain the same information—the number that identifies your line with the carrier—and only the physical size of the cutout changes. If you ever had to "cut" an old SIM to fit a new phone, it was precisely to go from a standard SIM or micro SIM to a nano SIM.
The nano SIM is still perfectly valid today. The point of this article is not to say that it's obsolete, but to explain what alternative has appeared alongside it—the eSIM—and when, especially when traveling, one solves a problem that the other doesn't solve as well.
What is an eSIM?
An eSIM (embedded SIM) is a chip permanently soldered inside the phone during manufacturing. Instead of inserting a physical card, you install a digital profile—usually by scanning a QR code—which activates a line or data plan on that integrated chip. There's no tray, no card to lose or cut.
The key difference for travelers is this: because the profile is digital, you can buy, install, and activate it without going to a physical store or waiting for a card to arrive by mail. You buy the data plan, scan the QR, and within minutes you have internet access on your phone, even before boarding the plane.
The same eSIM-enabled phone can store multiple profiles and use two lines simultaneously: the physical one (nano SIM) with your usual number, and the digital one with the data plan you bought for the country you're visiting. This is exactly what solves the typical roaming problem: continuing to receive calls and verification messages on your home number while using local data without roaming charges.
To understand the full concept, including how it works internally, you can review the guide what is an eSIM.
eSIM vs nano SIM: Differences that matter when traveling
Both essentially do the same thing—identify you to a mobile network—but they differ in how they are installed, how they are changed, and how easy it is to use them in multiple countries during the same trip. The following table summarizes the differences that truly affect someone planning an itinerary, not the technical manufacturing differences.
| Feature | Nano SIM (physical) | eSIM (digital) |
|---|---|---|
| How it's installed | By inserting the card into the phone's tray | By scanning a QR code or installing the profile from settings |
| Where to get it | At a carrier store, airport, or physical point of sale | Online, before traveling |
| Risk of loss or damage | Can be lost, bent, or untraceable in luggage | No physical support to lose |
| Changing plans at destination | Requires finding a local point of sale | Another profile can be bought and installed without leaving the hotel |
| Simultaneous use with your local line | Only if the phone has a dual physical tray | Coexists with your nano SIM in the same phone |
| Compatibility | Practically all phones since 2012 | Only recent models with integrated eSIM chip |
If you want to delve deeper into this comparison with more technical detail, the guide SIM vs eSIM covers network and coverage aspects that we only summarize here.
Can a nano SIM be converted to an eSIM?
No, not physically. A nano SIM is a card with a chip soldered to it; an eSIM is a distinct chip, soldered to the phone's board from the factory. There is no process that "transforms" the card into the integrated chip, because they are two separate pieces of hardware.
What does exist—and is probably what you're looking for if you came to this question—is transferring your current line from one format to the other. This depends on your carrier: some allow you to convert your number from a physical nano SIM to an eSIM profile from their app or call center, provided your phone has an eSIM chip. This process is handled by your primary line's carrier, not an eSIM provider for travel.
If, however, your goal is to have mobile data in another country without touching your usual line, you don't need to convert anything: you install an additional eSIM profile just for data, and your nano SIM continues to function in parallel for calls and messages. This is the simplest route and avoids any hassle with your local carrier.
The correct question is almost never "how do I convert my SIM?", but rather "do I need a new line or just data for a trip?". The answer completely changes the path forward.
Which is better, eSIM or nanoSIM? It depends on your trip
There's no single answer: neither is inherently better; each is better suited to a different situation. The following table organizes it by scenario, which is how this decision is actually made before a trip.
| Situation | Better suited for | Why |
|---|---|---|
| Short trip to a single country | eSIM | Installed before leaving, no need to find a point of sale upon arrival |
| Trip through several countries on the same itinerary | eSIM | You can change plans between destinations without new cards |
| Old phone without eSIM chip | Nano SIM | It's the only physical option compatible with that device |
| Need to keep your local number active for SMS or calls | Both at once | The eSIM covers data at the destination, the nano SIM continues to receive your line |
| Staying a long time at the destination | Local Nano SIM | A local line is usually better for prolonged use and formalities |
| Bought an unlocked phone and only concerned about installation | eSIM | Avoids relying on finding an open store at the destination |
In any of these scenarios, the important thing is to decide based on your actual itinerary and not on which technology sounds newer: both are still valid for different cases.
Real-life example of a trip with an eSIM
To make it clear how this looks in practice, imagine a typical trip: someone flying from Mexico City to Lisbon for ten days, with a two-night layover in Madrid on the way back. Their phone has a nano SIM with their usual Mexican line, which they use for banking and for family to call them.
A few weeks before the flight, they buy an eSIM data plan for Europe online and install the profile by scanning the QR code from home, without any airport rush. The plan is saved on the phone, but not yet activated: that only happens when the phone connects to a network at the destination, so they don't lose days of use by installing it in advance.
Upon landing in Lisbon, they activate the data plan in airplane mode for a moment before getting off the plane, and by the time they turn on their phone in the arrivals hall, they already have internet: map, messaging, hotel reservation. Their Mexican line remains on the nano SIM, receiving bank verification SMS without needing to activate international roaming with their usual carrier, which is usually charged separately and with rates that vary by carrier and date.
This is exactly the type of situation—moving between countries without relying on physical stores or the local carrier's roaming coverage—that the guide eSIM vs physical SIM compares in more detail when it comes to itineraries with more than one destination.
Is my phone compatible with eSIM?
Not all phones come with an integrated eSIM chip, and among those that do, some are locked for eSIM depending on the region or carrier where they were originally purchased, even if the hardware is present. That's why it's advisable to check this before buying any eSIM data plan, not afterwards.
The most reliable way to find out is directly from your phone's settings: most devices will have an option to "add eSIM" or "add data plan" within the mobile network menu. If that option exists, your phone is compatible; if it doesn't appear, it's probably not, or it's locked by the carrier.
Since the list of compatible models changes with each new release, the guide eSIM compatible phones keeps the details updated by brand and model, which we don't repeat here to avoid being outdated in a few months.
How to activate your eSIM step-by-step
The process is short and doesn't require technical knowledge, but it's best to follow the correct order to avoid wasting data prematurely. Generally, the steps are:
- Confirm that your phone is compatible with eSIM (see previous section).
- Purchase the data plan for your destination and receive the QR code, usually by email.
- Go to mobile network settings and install the profile by scanning that QR, ideally with Wi-Fi available.
- Leave the profile installed but not activated until the day of your trip, if installed in advance.
- Upon arrival at your destination, activate the mobile data for that eSIM line and deactivate roaming for your main line to avoid charges.
The complete process, with screenshots of each screen according to the operating system, is in the guide how to install an eSIM. It's worth reviewing if this is your first time installing one, as the exact names of the menus change between phone brands.
A little-known detail: since the plan doesn't activate until it connects to a network at the destination, you have 180 days from purchase to install and use it whenever you want. This means that buying the data plan weeks in advance—when you have plenty of time to set it up correctly—doesn't make you lose a single day of the days you'll use on your trip.
Common errors when switching from nano SIM to eSIM
Most problems when using an eSIM for the first time are not technical failures, but steps skipped due to rushing before a flight. The most frequent are:
- Installing the QR without Wi-Fi. The installation process requires an internet connection; if you try to do it with mobile data off and no Wi-Fi, it will be incomplete.
- Confusing "install" with "activate." The profile can be installed days in advance, but data consumption doesn't start until you activate that line, usually at the destination.
- Not checking which line is set as primary for data. If you don't configure correctly which SIM uses mobile data, your phone might continue trying to use your local line and generate roaming charges without you realizing it.
- Accidentally deleting the profile when changing phones. An eSIM profile doesn't always automatically transfer when changing devices; it's advisable to check the transfer process before resetting the old phone to avoid losing the active data plan.
If something doesn't work as expected, the guide common eSIM problems covers these cases in more detail and their solutions. And if the problem persists, support is available 24/7 in all languages via email and WhatsApp, without needing a phone call.
Frequently Asked Questions
What are nano SIM and eSIM?
A nano SIM is a physical card inserted into the phone; an eSIM is a chip integrated into the device's board where a digital profile is installed, usually via a QR code, instead of a card.
How to convert a nano SIM to an eSIM?
It's not possible to physically convert a nano SIM card into an eSIM chip, because they are different pieces of hardware. If you want to transfer your current number to an eSIM, that process is managed by your carrier; if you only need data for a trip, you can install an additional eSIM profile without touching your main line.
Which is better, eSIM or NanoSIM?
It depends on the use: for short trips or trips to several countries, an eSIM is usually more practical because it's installed before leaving. For phones without an eSIM chip, or for a local line for prolonged use, the nano SIM is still the appropriate option.
What is the nano SIM chip?
It is the smallest and most current SIM card size among the three physical formats (standard SIM, micro SIM, and nano SIM), and the one used by most phones manufactured from 2012 onwards.
Do I need to remove the nano SIM to use an eSIM?
No. On most compatible phones, the eSIM and nano SIM work simultaneously, each with its own active line or data plan.
Does the eSIM work without Wi-Fi?
To install the profile for the first time, you do need an internet connection (Wi-Fi or data). Once installed and activated, the eSIM works just like any physical SIM: it uses the country's mobile network, it does not depend on Wi-Fi.
How long does it take for an eSIM to activate?
The profile installation and data activation usually complete in approximately 1 minute once you have the QR code and an internet connection to install it.
What happens if I change phones after installing the eSIM?
The eSIM profile is tied to the physical chip of the device, so it does not always automatically transfer to a new phone. It is advisable to check the transfer process before resetting or disposing of the old device to avoid losing the active data plan.
Conclusion: Which one is right for you?
If your phone has an eSIM chip and you're traveling—whether to one country or several—installing an eSIM profile before you leave usually saves you time, queues, and the uncertainty of finding a point of sale in an unfamiliar place. Your nano SIM continues to work with your usual number, and the eSIM handles data at your destination.
If your phone is older or doesn't have an eSIM chip, a local nano SIM is still a valid option, it just requires more hassle once you arrive.
To take the first step without errors, the definitive eSIM guide for travel gathers the entire process from start to finish, and you can check available plans by country in the international eSIM collection, which covers more than 200 destinations with 24/7 support in all languages via email and WhatsApp.
