What is an eSIM and how does it work?

Key takeaways

• An eSIM (short for embedded SIM) is a SIM built into a phone as a tiny chip, so you can set up a mobile plan digitally without a physical SIM card.
• An eSIM works by downloading a small digital file, called a profile, that holds the details of a mobile plan, usually by scanning a QR code while connected to Wi-Fi.
• Most phones made in the last few years support eSIM, and switching from a physical SIM to an eSIM on the same network doesn't change your number.

 

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Your friend swears by it. Your network keeps emailing you about it. Everyone seems to be telling you to get an eSIM, but nobody has quite explained what it is.

Here’s what an eSIM is, how it works and what to check before you switch.

What is an eSIM?

An eSIM is a digital SIM built into your phone, so you can get connected without a physical SIM card.

A normal SIM is the tiny plastic card that links your phone to your number and plan. An eSIM does the same job, just without the card. Your plan is set up on the phone itself, so there's no tray to open and no need to hunt for the ejector pin.

Think of it as swapping a paper boarding pass for the one on your phone. Same trip, less faff.

How does an eSIM work?

An eSIM works by downloading a small digital file, called a profile, to a chip already built into your phone. The profile holds the same details as a physical SIM: which network you're with, your phone number and your plan.

Once the profile is installed, your phone connects to the network in exactly the same way it would with a physical SIM.

How to install and activate an eSIM

The exact steps vary by phone and network, but they usually look like this:

1. Get your eSIM details from your network, usually a QR code sent by email or shown in the network's app.
2. Connect your phone to Wi-Fi so it can download the eSIM.
3. Open your phone's SIM or mobile settings and choose to add an eSIM.
4. Scan the QR code, then enter a confirmation code if you're asked for one.
5. Turn Wi-Fi off, then make a call or send a text to check you're connected.

Most people are up and running in a few minutes. If you're joining SMARTY, our eSIM setup guide walks you through each step.

Is an eSIM better than a physical SIM?

Neither is better for everyone. But an eSIM is handy if you want to get connected quickly, switch networks without waiting for a card in the post, or run two numbers on one phone. Here's how the two compare in everyday use:

What you're doing	eSIM	Physical SIM
Getting started	Set up digitally, often within minutes of receiving a QR code	Needs a card to be posted or collected, then inserted
Switching network	Done by installing a new profile, with no card involved	Needs a new card from the new network
Moving to a new phone	Usually means asking the network to move it, or using the phone's transfer tool	Take the card out of the old phone and put it in the new one
Losing a phone or having it stolen	Can't be taken out and used in another phone	Can be taken out and used elsewhere unless a SIM PIN is set
Phone compatibility	Needs a phone that supports eSIM and isn't locked to another network	Works in almost any phone with a SIM tray
Running two numbers	Many phones let an eSIM sit alongside a physical SIM for two lines on one phone	Needs a phone with two SIM trays, or a second phone

Which phones support eSIM?

Most phones made in the last few years do, including recent iPhone, Samsung Galaxy and Google Pixel models. Support varies by model. Not sure about yours? Our guide to eSIM-capable devices lists the phones that support it.

Getting an eSIM with SMARTY

If an eSIM suits you, SMARTY is a good place to get one. Whether you want a SIM-only plan or a data SIM, you can choose eSIM at checkout, so you don't have to wait for a SIM to arrive by post. Pick a plan, choose eSIM, and you can be up and running in a few minutes.

Want to know more? Our eSIM page has the details. Ready to go? Browse all our plans.

FAQs

1. Is an eSIM safer than a physical SIM?

An eSIM is generally as secure as a physical SIM, and safer in one way: it can't be taken out of a stolen phone and used in another. It doesn't protect against scams where someone tricks a network into moving a phone number, so keeping your account details private and using a strong phone passcode still matters.

2. Can I change my physical SIM to an eSIM?

Usually, yes, as long as the phone supports eSIM and the network offers it. The network sends a QR code or activation details, and your number stays the same.