What is an eSIM?

An eSIM is an electronic SIM embedded in your smartphone that can’t be physically removed like a standard SIM card. You’re not locked into one network as the eSIM can change provider with you. Here are your need-to-knows about this emerging technology.

How does an eSIM work?

An eSIM is a tiny chip that can be programmed and updated to work with any mobile network that supports eSIMs.

To set up an eSIM, you ask your mobile network operator to send you an eSIM pack. It will contain a QR code, which you’ll need to scan with your phone’s camera. This information will be sent back to your provider, who will activate your eSIM securely for you. You can store more than one network on your eSIM, but you’ll only be able to use one at a time.

Some phones now come with eSIM capability, as well as a plastic SIM card slot. These are called Dual SIM with an eSIM.

What are the advantages of an eSIM?

Thanks to the advances in SIM card technology, there are many benefits of eSIMs. You can:

  • Switch networks easily – if you’re switching from one phone network to another, you won’t have to wait for a new SIM card and a porting authorisation (PAC) code. You can switch there and then.

  • Store multiple networks – an eSIM allows you to store more than one network, so you’ll be able to switch quickly between them. This is useful in the event of a lost signal, or if you’re in an area not covered by the network you’re using.

  • Save space – an eSIM is even smaller than a nano SIM, so it takes up less room on your phone. In future, smartphone makers may use this extra space to add a larger battery and other features.

  • Avoid roaming charges – if you’re travelling abroad, you can have a data tariff with a local network carrier, without needing to swap SIMs.

What are the disadvantages of an eSIM?

There are a few potential downsides to not having a physical SIM. These could include:

  • Data transfer complications – with a physical SIM, it’s straightforward to transfer your personal information to another phone. But with an eSIM, you might not be able to transfer data from one phone to another very easily, unless you use cloud storage.

  • Privacy concerns – while eSIMs are secure and can be reprogrammed, they can’t be taken out of the device. This has given rise to concerns about them being trackable and users’ personal details being hacked.

Which mobile networks support eSIMs?

The technology is still relatively new and not all mobile providers are on board with it yet, but the UK’s four biggest mobile networks are – namely O2, EE, Three and Vodafone. It’s only a matter of time before take-up grows and even more of us will be able to use it.

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Kate Moss-Robins
Written byKate Moss-RobinsPersonal finance and utilities specialist

Over the past decade, Kate has worked in various industries, including company secretarial, small business support and property investing.

Her move to financial services in 2022 not only helped her find her niche in personal finance writing, but also just how alienating finance can be. She’s now motivated by making everyday money a piece of cake for everyone, helping her readers feel informed and in control.

Kate now specialises in savings and current accounts as well as broadband, mobile and energy products.

Ele Clark
Edited byEle ClarkPersonal finance and insurance expert

Ele Clark is an award-winning editor who has held leadership roles at Which? and news-stand publications in London and Dubai. She’s appeared across the press and media, including BBC’s Panorama. With almost 20 years’ experience in personal finance, insurance and consumer journalism, she leads a talented team at Compare the Market, creating insightful, accessible content to help people make informed financial decisions.

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With the UK racing towards gigabit speeds and our phones more integral to our lives, Matt wants to make sure you have great packages that can keep up. And with more than 10 years' experience working with digital brands, he’s shaping our broadband, TV and phone comparison journeys.

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