For thirty years, getting a phone onto a mobile network meant a plastic SIM card: a shop, a pin to open the tray, and a tiny card you hoped not to drop. An eSIM does the same job with no card at all. This page explains how it works, how it compares with a physical SIM, and when it is (and isn’t) the better choice.
How an eSIM works
Every SIM, plastic or embedded, holds a profile: the credentials that tell a mobile network who you are and which plan you’re on. On a physical SIM the profile is written at the factory, so changing plans means changing cards. An eSIM is a small chip soldered inside the phone that can download a profile over the internet, store several at once, and switch between them.
When you get an eSIM plan, three things happen:
- The provider creates your profile and gives you a way to download it: a QR code, an activation code, or a one-tap install link.
- Your phone downloads it over Wi-Fi or mobile data and adds it as a new line in Settings, next to your existing SIM.
- The phone connects to the network that profile belongs to, exactly as it would with a SIM card.
The chip itself has a unique ID called an EID, which is why dialling *#06# is the fastest way to tell whether a phone has one. There’s more on that in our eSIM compatible phones list.
eSIM vs physical SIM
Both connect you to the same networks at the same speeds. The difference is everything around the connection:
| Feature | eSIM | Physical SIM |
|---|---|---|
| What it is | A chip built into the phone, rewritten over the internet | A removable plastic card |
| Getting a plan | Buy online, install in about two minutes from anywhere | Visit a shop or wait for delivery |
| Plans per phone | Several stored, usually two active at once | One per SIM slot |
| Switching plans | A toggle in Settings | Swap the card with a SIM tool |
| If the phone is stolen | Can’t be removed and reused | Can be pulled out and used elsewhere |
| Phone support | Most phones from 2018 onward | Almost every phone |
The advantages of an eSIM
- Nothing to wait for. You can buy and install a plan from your sofa, an airport lounge, or a hotel room abroad. No shop, no post.
- Two lines in one phone. Keep your normal SIM for calls and texts while an eSIM handles data, or run a work and a personal number side by side.
- Several plans stored. Phones can keep multiple eSIM profiles and switch between them in Settings, which suits people who travel often.
- Harder to steal. An eSIM can’t be pulled out of a lost phone and put into another one.
- No tiny card to lose. Especially welcome when you’d otherwise be swapping SIMs in an airport arrivals hall.
The disadvantages
- Your phone has to support it. Most phones since 2018 do, but older and budget models, and some sold in particular regions, don’t.
- Moving to a new phone takes a step. You can’t just move a card across; an eSIM usually has to be transferred or reissued by the provider.
- Installing needs an internet connection. Easy at home on Wi-Fi, less so if you only think of it after landing somewhere with no Wi-Fi.
- Locked phones won’t take one. A phone locked to your home carrier will refuse another provider’s eSIM, just as it would their SIM card.
The last two are why the usual advice is to check your phone is unlocked and install the eSIM before you fly. Both take a couple of minutes at home and remove most of what can go wrong on arrival.
Why travellers use eSIMs
Travel is where an eSIM makes the biggest difference. The alternatives all cost something: roaming on your home plan is usually the most expensive data you can buy, a local SIM means finding a shop and removing your own SIM, and a pocket Wi-Fi is one more device to charge and return.
A travel eSIM is a prepaid data plan for the country or region you’re visiting. You install it before you leave, it runs on local networks when you arrive, and your home SIM stays in the phone the whole time, so you still receive calls and texts on your normal number. With SimKit, the plan’s validity only starts when the eSIM first connects at your destination, so buying early never costs you days.
Does an eSIM give you a phone number?
Some eSIM plans do; many travel eSIMs, SimKit’s included, are data-only. In practice that’s what most travellers want: your home SIM keeps your number for calls and texts, and WhatsApp, iMessage and FaceTime carry on as normal over the eSIM’s data.
Ready to try one?
First, check your phone supports eSIM. Then read how to install and use an eSIM, which covers iPhone, Samsung and Pixel step by step and the three settings to change when you land.