An eSIM is a digital version of a physical SIM card that is built into a compatible phone or device. It lets you activate a mobile plan by downloading it to your phone rather than inserting a plastic card. This guide explains how eSIM works, how to check whether your phone supports it, and which UK networks offer it on pay monthly, SIM only and pay as you go plans.
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Reviewed by: Phil Brown, founder of SIM Only Finder. Phil previously worked in UK mobile retail at Three UK, advising customers on SIM plans, contracts, and network choices. He has spent over a decade running consumer comparison platforms and reviews networks and SIM-only deals based on that hands-on industry background. About the author
Last reviewed: September 2026. Updated regularly to reflect network support, activation processes and eSIM availability.
How we put this guide together
To put this guide together, we reviewed eSIM availability across UK networks in September 2026, checking each network's published eSIM help pages, ordering journeys and device support information directly against their own websites. Where a network's public information was unclear, for example on whether eSIM is available at online checkout or only through customer services, we have said so in the table rather than assuming support. Where relevant, we have drawn on our own experience of ordering and activating eSIMs across UK networks and MVNOs.
Which UK networks support eSIM?
All four UK network operators, EE, O2, Three and Vodafone, offer eSIM, and so do a growing number of virtual networks that use their infrastructure. The detail is where it gets more complicated. Some networks only offer eSIM on certain plan types, some will not let you order one online, and a small number still restrict it to specific devices.
The table below shows what each network offered when we last checked. "Online" means you can select eSIM at checkout or through the network's app or account area without calling or visiting a store. "n/a" means the network does not sell pay as you go at all, rather than that eSIM is unavailable on it.
Three things stand out from that table. First, plan type matters more than the network name. EE and O2 both support eSIM widely on pay monthly, but EE does not offer it on pay as you go at all and O2 only offers it in store. If you want a pay as you go eSIM, our guide to which networks offer eSIMs on pay as you go goes through each option in detail.
Second, "supports eSIM" does not always mean "supports eSIM online". Tesco Mobile is the clearest example: the eSIM works normally once installed, but you have to ask customer services or visit a store to get one, and unless you are buying a pay monthly phone the QR pack arrives by post. That removes most of the speed advantage of going digital.
Third, a few networks limit eSIM by device rather than by plan. Lebara launched eSIM in October 2025 but had still not opened it up beyond the iPhone Air for new customers when we checked. 1pMobile ties eSIM to a price threshold instead. If you are on a budget plan or an unusual handset, check the network's own eSIM page before you commit.
Best for: Anyone with a compatible phone who wants same-day activation on a pay monthly or SIM only plan has plenty of choice. Pay as you go users have fewer options and should start with the dedicated PAYG guide above.
Once you have confirmed your phone and plan type are supported, you can compare UK eSIM only deals from supported networks on our dedicated deals page.
How does an eSIM work?
A physical SIM stores a small profile that tells the network who you are and which plan you are on. An eSIM stores exactly the same profile on a chip that is soldered inside your phone. Instead of posting you a card, the network sends the profile over the internet and your phone writes it to that chip.
The activation process is broadly the same across networks, though the exact steps vary by network and device:
- Choose an eSIM-compatible plan and select the eSIM option when ordering, where the network allows it.
- Receive an activation link, a QR code by email, or an instruction to install the eSIM through the network's app. Some networks, such as EE and O2, also let you install directly from your online account.
- Add the plan through your phone's settings. On most phones this means scanning the QR code with the camera or tapping the link, then following the on-screen prompts.
- Choose whether the eSIM is your primary line or a secondary one if you already have a SIM installed.
- Transfer your existing number using a PAC if you are switching networks. Number transfers usually complete the next working day.
You will need Wi-Fi or another data connection during the download, because the profile has to reach the phone before it can connect to the network on its own. Once installed, the eSIM works like a physical SIM and needs no ongoing connection to stay active.
One point worth knowing before you start: most networks tie an installed eSIM to the phone it was installed on. Tesco Mobile, for example, allows up to three activations from a single QR code on the same phone but requires a replacement eSIM to move to a different handset. Keep your QR code or activation email safe until you are sure you no longer need it.
Is my phone compatible with eSIM?
Most phones sold in the UK in the last five or six years support eSIM, but support is not universal, particularly on cheaper Android handsets. The quickest check that works on almost any phone is to dial *#06# as if it were a phone number. If your phone shows an EID alongside the IMEI, it has an eSIM chip. If there is no EID, it does not.
You can also look in the settings:
- iPhone: go to Settings, then Mobile Service (or Mobile Data on older iOS versions). If you see an Add eSIM option, your phone supports it. Every iPhone from the XS, XS Max and XR onwards has eSIM, and the iPhone Air has no physical SIM tray at all.
- Samsung Galaxy: go to Settings, then Connections, then SIM manager. An Add eSIM option confirms support. Galaxy S20 and later, the Z Fold and Z Flip ranges, and selected A series models from around the A54 onwards support eSIM, but check your exact model because support in the A series varies.
- Google Pixel: go to Settings, then Network and internet, then SIMs. Look for an option to add or download a SIM. Pixel 3 and every later model support eSIM.
- Other Android phones: the path is usually Settings, then Network and internet or Connections, then SIMs or SIM cards. If you cannot find an option to add an eSIM, use the *#06# check or look up the specification on the manufacturer's website.
Two caveats apply even if your phone passes the check. A phone bought in mainland China or Hong Kong may have two physical SIM slots and no eSIM, even if the same model sold in the UK has one. And a phone that supports eSIM technically may still be locked to another network, in which case you will need to unlock it before an eSIM from a different network will work.
Finally, device support and network support are separate questions. Your phone can be fully eSIM capable and a particular network or plan may still not offer one, as the table above shows for pay as you go on EE or for most devices on Lebara. Check both before you order. For help identifying which SIM type your phone takes more generally, see our guide to what SIM card you need for your phone.
Can I keep my existing number?
Yes. Moving to an eSIM does not change how number transfers work in the UK. If you are switching networks, text PAC to 65075 from your current phone, give the code to your new network when you order or after your eSIM is active, and the number moves across, normally by the end of the next working day. Our PAC code guide walks through the process step by step.
It helps to be clear about which of three situations you are in, because the process differs:
- Converting an existing physical SIM to an eSIM on the same network. No PAC is needed. Your network issues an eSIM and moves your number and plan onto it, usually through the app, your online account or customer services. On some networks the physical SIM stops working as soon as the eSIM is activated, so make sure you are ready before you start.
- Moving to another network and porting your number. You need a PAC from your old network. Order the eSIM from the new network first, then submit the PAC. Your old service closes when the transfer completes, although any outstanding contract charges will still apply.
- Adding an eSIM as a second line. No PAC is needed and your existing number stays as it is. The eSIM comes with a new number and runs alongside your current SIM.
If you are on a network that only issues eSIMs by post or in store, such as Tesco Mobile, factor that delay into your PAC timing. A PAC is valid for 30 days, so there is usually time, but you do not want it to expire while you wait for a QR pack.
Can I use an eSIM and a physical SIM together?
On most modern phones, yes. Dual SIM with eSIM means the phone runs a physical SIM and an eSIM at the same time, each with its own number. Newer iPhones can also run two eSIMs together, and the iPhone Air relies on that because it has no SIM tray.
The common ways people use this:
- Personal and work numbers on one handset, so you can leave the work line switched off outside working hours.
- A UK SIM alongside a travel plan when you go abroad. Your UK number stays reachable for calls and texts while a local or travel eSIM handles data. Our guide to whether eSIMs are only for travel explains the difference between a travel package and a regular UK eSIM plan.
- Separate lines for calls and data, for example a cheap voice plan on one SIM and a large data allowance on the other.
Your phone will ask which line to use for calls, texts and data, and you can change that at any time in settings. Contacts can be assigned to a particular line so that calls to a given person always go out from the right number.
There are limits. Both lines share the phone's radio, so on many handsets only one line can be on a call at a time, and the other may go to voicemail. Not every phone supports 5G on both lines simultaneously. And some networks do not support companion eSIMs for smartwatches, which is a different feature from dual SIM on a phone: Tesco Mobile, Lebara and EcoTalk all say they do not.
Does eSIM support 5G?
An eSIM does not decide which network technology you get. Whether you connect over 4G or 5G depends on four things: your handset, the plan you are on, the network's 5G coverage where you are, and whether the network has enabled 5G on your account. An eSIM and a physical SIM on the same plan and the same phone will perform identically.
The confusion usually comes from budget plans. Some networks reserve 5G for higher tiers, and some MVNOs have only recently added it. If 5G matters to you, check that the specific plan includes it rather than assuming the eSIM format has any bearing. The same goes for signal strength and battery life: the eSIM chip draws no meaningful extra power and does not change how the phone's antenna performs.
Advantages and disadvantages of eSIM
eSIM is a better fit for some people than others, and it is worth weighing both sides rather than assuming digital is automatically superior.
Potential advantages
- Nothing to insert, lose or damage. The profile lives inside the phone.
- Faster activation. On networks that support online ordering, you can be connected within minutes rather than waiting for the post.
- Easier to hold more than one plan on the same phone and switch between them.
- Well suited to dual SIM use and to adding a travel plan without removing your main SIM.
- Harder for someone who steals your phone to remove the mobile service immediately.
- No plastic card or packaging.
Potential disadvantages
- Not supported by every phone, network or plan. Pay as you go and cheaper handsets are the most common gaps.
- Moving to a new phone is not always a two-minute job. On most networks you need a replacement eSIM, which some issue instantly through an app and others send by post or only in store.
- If your phone breaks and will not switch on, you cannot pull the SIM out and put it in a spare. You need the network to reissue the profile.
- Troubleshooting can require network assistance. A physical SIM can be tested by moving it between phones; an eSIM cannot.
- Some networks still impose restrictions, such as store-only activation, device limits or a small number of activations per QR code.
For most people on a pay monthly or SIM only plan with a recent phone, the advantages outweigh the drawbacks. For someone who changes handsets frequently or relies on swapping a SIM into a backup phone, the physical card may still be the simpler option.
Who should choose an eSIM?
The right answer depends on how you use your phone. These are the situations where eSIM makes the most sense, and the ones where a physical SIM still has the edge.
You want two numbers on one phone. eSIM is the obvious choice. Keep your existing physical SIM for one line and add the second as an eSIM, or run two eSIMs if your phone supports it. Work and personal, or a main plan plus a cheap data-only line, both work well this way.
Best for: Anyone juggling a work and personal number who does not want to carry two handsets.
You change or compare plans often. eSIM removes the wait for a SIM in the post, so you can move to a better deal the day you find it. This works best on networks that issue eSIMs online and on rolling 30-day SIM only deals that do not tie you in.
Best for: Deal-hunters on rolling plans who want to switch as soon as prices move.
You travel abroad regularly. Keep your UK plan on one line and add a travel eSIM for data on the other. Your UK number stays live for calls and texts, and you avoid roaming charges on data.
Best for: Frequent travellers who want to keep their UK number reachable without paying UK roaming rates for data.
You have a compatible phone and want to be connected today. If your network supports online eSIM ordering, there is no reason to wait for the post.
Best for: New customers on EE, Vodafone, Three, giffgaff, SMARTY, VOXI, iD Mobile or any other network with checkout eSIM.
You swap SIMs between devices. This is where a physical SIM is still simpler. If you regularly move one plan between a phone, a tablet and a spare handset, or you keep an old phone as a backup for when your main one is being repaired, the ability to pull the card out matters. A physical SIM is also the practical choice if you are on a network that only issues eSIMs by post or in store, or if your phone fails the compatibility check above.
Best for: People who treat their SIM as portable, or who are on pay as you go with EE or O2.
Frequently asked questions
Is an eSIM better than a physical SIM?
Neither is better in terms of signal, speed or price. An eSIM is more convenient for activation and dual SIM use, and a physical SIM is more convenient for moving between phones. Choose based on which of those you do more often.
Can I switch back to a physical SIM?
Yes, on any network that issues physical SIMs. Contact your network and ask for one. Once it arrives and is activated, your number and plan move across and the eSIM profile is deactivated. Some networks charge a small replacement fee. The exception is a phone with no SIM tray, such as the iPhone Air, where a physical SIM is not an option at all.
Can an eSIM be transferred to a new phone?
Usually, but the method varies. Recent iPhones can transfer an eSIM directly during setup on some networks, including EE. On most other networks you request a replacement eSIM, which some provide instantly through an app or online account and others post as a QR pack or issue in store. Tesco Mobile, for instance, sends replacements by tracked post.
Can I have more than one eSIM?
Yes. Most eSIM phones can store several profiles and keep one or two active at a time. You can hold a UK plan and a travel plan side by side and switch between them in settings.
Do I need Wi-Fi to activate an eSIM?
You need an internet connection to download the profile, and Wi-Fi is the simplest way to get one when the phone has no other active SIM. If you already have a working SIM in the phone, its data connection will do the job.
Can I keep my number when moving to an eSIM?
Yes. Converting on the same network keeps your number automatically. Moving to a new network needs a PAC, exactly as it would with a physical SIM.
Does eSIM affect signal strength or battery life?
No. The eSIM chip stores your profile and nothing else. Signal and battery depend on the phone's radio and the network, not on the SIM format.
Conclusion
An eSIM is the same plan delivered a different way. It does not change your coverage, speed or price, but it does change how quickly you can get connected and how easily you can run more than one line. All four UK network operators and a growing number of virtual networks now offer it on pay monthly or SIM only plans, with pay as you go and a handful of device-restricted networks the main remaining gaps.
The one trade-off worth keeping in mind is moving phones: a physical SIM can be swapped in seconds, whereas an eSIM needs a reissued profile. For most people that is a minor inconvenience once every couple of years. For someone who swaps devices weekly, it may be reason enough to stick with plastic.
How to get an eSIM
Dial *#06# to confirm your phone shows an EID, then check the table above to make sure your chosen network offers eSIM on the plan type you want. Ready to make the switch? Compare UK eSIM only deals from supported networks, order with the eSIM option selected, and install the profile from the QR code, link or app instruction the network sends you. If you are keeping your number from another network, text PAC to 65075 before you order and hand the code over at sign-up or once the eSIM is active; the PAC code guide covers the transfer in full.
If you would rather stay on pay as you go, start with our guide to Pay As You Go eSIM networks, which explains which networks offer one and how each activation process works.
Editorial policy
This guide is produced by the SIM Only Finder editorial team to help UK consumers understand eSIM technology and compare eSIM availability across UK networks. Network support, activation processes and eSIM availability are checked regularly and updated to reflect current information. Always confirm current terms directly with the network before signing up.
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