What is an eSIM?
A SIM card that you download to your phone instead of buying a piece of plastic and slotting it in. It does the same job as the usual one: it connects you to a network.
How it differs from a regular SIM
The plastic one
You have to get hold of it: a shop, an airport counter or the post. You swap it by hand, with the little pin. While you use it, your own SIM sits loose in your wallet, and when you get home it ends up in a drawer.
The digital one
It downloads in a couple of minutes from your phone’s settings. It sits alongside the SIM you already have, so you keep your number. When the trip is over, you delete it and that’s that.
To the mobile network, the two are the same. The difference is how the card gets to your phone, not how it works once it’s there.
How it works
Your phone already has the chip inside
Recent phones come with a small chip soldered to the board that does the job of the SIM card. It has its own identifying number, the EID, and it’s built in at the factory: you don’t buy it or change it.
The operator prepares a profile
What used to be stored on the card (your line, with its permission to use a network) is now a file. The operator prepares it and leaves it waiting on a server, reserved for a single phone.
The QR code only says where to collect it
This is where people usually get confused: the QR code is not the eSIM. It’s an address. When you scan it, your phone knows which server to go to and which profile to ask for; it downloads it and stores it on the chip. That’s why you need internet to install it, and why a QR code only works once.
Once downloaded, the profile lives inside your phone. You can lose internet, switch the phone off or fly: the eSIM stays there.
What it’s for, and what it isn’t
Travel eSIMs, like Glowi’s, are data-only: they give you internet on your phone in another country. That means maps, messaging, social media, email and calls through apps. It also means there are three things it doesn’t do:
It has no phone number. You can’t receive calls or texts on that line.
It doesn’t replace your SIM. It sits alongside it; your usual line stays where it is.
You can’t make calls over the mobile network with it. You can call over WhatsApp, FaceTime or any other app.
Why this changes things when you travel
Away from home, the usual problem was choosing between paying your home operator’s roaming charges or hunting for a local SIM card as soon as you landed. The eSIM takes that choice away.
You don’t depend on roaming. You buy data for the country you’re going to, at its price, before you leave.
No hunting for a shop when you arrive. No counter, no passport, no queue with your phone on 4%.
You keep your number. Your usual line stays in, so texts from your bank and your contacts keep arriving.
Does my phone support it?
Most phones from the last few years do. The quick way to find out: dial *#06# as if you were making a call. If an EID appears among the numbers shown, your phone supports eSIM. It also needs to be unlocked.
Frequently asked questions
Is my phone compatible?
Dial *#06#: if an EID number appears, it supports eSIM. It also has to be unlocked.
Do I have to take out my current SIM?
No. Both lines live side by side on your phone: yours for calls and texts, Glowi’s for data.
Do I keep my number and WhatsApp?
Yes. Your SIM stays in; the eSIM only carries the data.
Can I make calls or receive texts with the eSIM?
No. It’s a data-only line: it has no phone number. For calls and texts you keep using your usual line, and over the internet WhatsApp, FaceTime and any other app work as normal.
How many times can I use the QR code?
Just once. The profile downloads once and after that the QR code is used up. If you delete the eSIM from your phone, you’ll need a new one.