An eSIM is a SIM card built into your phone. Instead of sliding a small plastic card into a tray, you download your mobile plan as a digital profile, usually by scanning a QR code or tapping a button in your network’s app. Every major UK network now supports it, and it can make switching phones or deals quicker. This guide explains how it works, how to set one up on iPhone and Android, and how to keep your number if you change provider.
What an eSIM is and who offers it
An eSIM works through a digital profile set up by your network provider, as SwitchGenius explains. The four main UK networks, EE, Vodafone, Three and O2, all offer eSIMs, and so do smaller brands such as giffgaff, iD Mobile, VOXI, Sky Mobile and Smarty. Saily reports that EE eSIM plans cost the same as physical SIM plans, but prices vary, so check your own deal.
On the phone side, Mighty Gadget notes that iPhones have supported eSIM since the iPhone XS in 2018. Google Pixel phones and many recent Samsung Galaxy models support it too, although Android support varies by manufacturer, so check your exact model before you buy a plan.
| Physical SIM | eSIM | |
|---|---|---|
| How you get it | A card posted to you | A QR code or app download |
| Changing phone | Move the card | Transfer or reissue the profile |
| Lost or stolen phone | Thief can remove the card | The profile cannot simply be pulled out |
| Dual SIM use | Needs a second tray | Often possible alongside a physical SIM |
What you need before you start
Vodafone says you need a stable Wi-Fi connection and a network-unlocked phone. In the UK, Ofcom says providers cannot sell locked phones, so most handsets should work. Have your account details ready, and keep your old SIM active until the new eSIM is working.
How to set up an eSIM on iPhone
- Open Settings and tap Mobile Service (some versions say Mobile Data).
- Tap Add eSIM, then scan the QR code your network gave you, or follow the prompt to use your network’s app.
- If you are moving from another iPhone, iD Mobile and other providers describe a transfer option that moves the plan from a nearby iPhone. Three says its Quick Transfer is currently only for iPhone customers.
- Finish any final steps on the network’s page and restart if the signal bars do not appear straight away.
How to set up an eSIM on Android
- Open Settings and search for Network and Internet or Connections, depending on your phone.
- Choose SIMs, then add an eSIM.
- Scan the QR code or follow your network app’s steps.
- Choose which SIM handles calls, texts and mobile data.
If you are moving from an iPhone to an Android phone, there is usually no direct transfer. As Your Business Number explains, you remove the eSIM from the iPhone and set it up again on the Android, which sometimes means asking your network for a new QR code. O2 notes that an eSIM is only active on one device at a time.
How to keep your number when you switch network
Changing provider is separate from changing to an eSIM. Ofcom’s Text to Switch service lets you text PAC to 65075 from your current number. Your provider must reply within a minute with a code that is valid for 30 days, and you give that code to your new provider. Ofcom adds that if your account has more than one number, such as a family plan, you need to request the code by phone or through your provider’s website instead.
Common problems and how to avoid them
- Deleting the old eSIM too early. Giant Networks warns this is a common cause of problems. Wait until the new profile is working.
- Reusing a QR code. Many codes only work once, so ask for a new one rather than trying again and again.
- Mixing up codes. Smarty points out that your confirmation code is separate from the QR code email.
- Buying a travel eSIM and expecting a UK number. Saily notes some prepaid eSIMs give data only, with no standard calls, texts or phone number.
Keep your account secure
Your phone number is tied to many accounts, so protect it. Use an authenticator app or a passkey instead of text-message codes where you can. Our guides to setting up two-factor authentication and passkeys explain how, and stopping spam calls and texts helps reduce scam attempts. If your phone feels slow after a move, try our tips to speed up a slow smartphone, and back up first with our phone photo backup guide.
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Frequently asked questions
Can I use an eSIM and a physical SIM together?
Often yes, on dual-SIM phones. Many phones can store several eSIM profiles but only use one or two at once, so check your handset.
Will my number move with my eSIM?
If you stay with the same network and just change phone, your number should come with the eSIM. If you change network, use Ofcom’s PAC process to keep it.
Is an eSIM more secure than a physical SIM?
It cannot be pulled out of a stolen phone, but your account can still be targeted, so use strong sign-in methods. If your phone is lost, contact your network straight away.
Does an eSIM cost more?
Not usually, though it depends on your provider and plan. Check before you switch.
Sources checked: Ofcom, Vodafone, O2, Three, iD Mobile, Smarty, SwitchGenius, Saily, Mighty Gadget, Your Business Number and Giant Networks. Menu names vary by phone and software version, and this is general guidance rather than advice for your specific handset.
