Which UK networks support eSIM?

All of them. EE, O2, Vodafone and Three each offer eSIM on compatible phones, and a growing number of the virtual networks (MVNOs) that run on them do too. Note that the UK now has three mobile network operators, not four: Vodafone UK and Three UK merged on 31 May 2025 to form VodafoneThree. They still sell and support eSIM as separate consumer brands, so the setup steps below are unchanged — but if you are adding a second eSIM for better coverage, a Vodafone and a Three SIM are no longer two independent networks. Check the specific plan, as availability can differ between pay monthly and pay as you go.

Can I keep my phone number when moving to an eSIM?

Yes. Moving from a plastic SIM to an eSIM on the same network keeps your number automatically. If you’re also changing network, request a switching code (a PAC to keep your number) from your current provider — it’s free — and give it to the new one.

Can I use an eSIM and a normal SIM at the same time?

On most modern phones, yes — that’s dual SIM. Your phone can hold a physical SIM and one or more eSIM profiles, with two active at once: two numbers, or one number plus a data SIM on a different network.

What happens to my eSIM if I break or lose my phone?

The eSIM profile lives in that phone, so you’ll need the network to issue a replacement profile (or use its transfer process) for the new device. It’s usually quick via the app or support — but unlike a plastic SIM, you can’t just move the card yourself, so sort it before travelling if you can.

eSIM in the UK: how it works and how to switch

An eSIM is a SIM built into your phone that you activate digitally — no plastic card. Every UK network supports eSIM — EE, O2, Vodafone and Three, which since the 2025 merger sit under three network operators rather than four — and setup usually means scanning a QR code or using the network’s app. eSIM makes it easy to run two numbers or networks at once, which is also a handy fix for patchy coverage.

An eSIM (embedded SIM) is a SIM that’s built into your phone. Instead of posting you a plastic card, the network sends a digital profile that you download — usually by scanning a QR code. It does exactly the same job as a physical SIM, but it’s faster to activate, impossible to lose, and lets one phone hold several networks at once.

Does my phone support it?

Most mid-range and flagship phones from the last few years do — iPhones since the XS/XR era, and most recent Samsung Galaxy and Google Pixel models. Two things to check:

eSIM capability — look in your phone’s settings for “Add eSIM” (iPhone: Settings → Mobile Service; Android: Settings → Network & internet → SIMs).
Network locking — a phone locked to one network can’t take another network’s eSIM until it’s unlocked. Ask your current provider; unlocking is typically free.

Setting up an eSIM

The process is similar on every UK network:

Order the eSIM — choose eSIM when buying a plan, or ask your network to convert your existing SIM. On EE, O2, Vodafone and Three you can do this in the app, online or in store.
Receive the activation details — usually a QR code (sometimes an in-app transfer that skips the QR entirely).
Scan the code from your phone: iPhone: Settings → Mobile Service → Add eSIM. Android: Settings → Network & internet → SIMs → Add eSIM.
Follow the prompts — you may enter a confirmation code, then choose whether the new line is your default for calls and data.
Wait for activation. It’s often instant but can take a few hours; keep the old SIM working until the new one has signal.

Each network’s own steps: EE · O2 · Vodafone · Three.

Keeping your number when you switch network

Switching network with an eSIM works the same as with plastic: ask your current network for a PAC (to take your number) — it’s free and they must give it to you promptly — then pass it to the new network when you activate. Your number moves over, usually within one working day.

The underrated trick: dual SIM for coverage

Because eSIMs are so easy to add, they’re a practical fix for patchy signal:

Two networks in one phone. Keep your main number, and add a cheap pay-as-you-go eSIM on a network that covers the places your main one doesn’t — different networks have genuinely different coverage maps. One caveat since the merger: Vodafone and Three are now the same operator (VodafoneThree, from 31 May 2025), so pairing those two brands no longer gives you two independent networks to fall back on. For genuine redundancy, pair across EE, O2 and VodafoneThree. See how to check the best network for your area.
Travel data. Add a local or travel eSIM abroad while your UK number stays active for calls and texts.
A backup when your network is down. A second-network eSIM plus tethering is a cheap safety net — the same idea as our backup internet planner.

If your underlying problem is weak signal at home, start with the fix mobile signal diagnostic — solutions like Wi-Fi Calling often beat buying anything.

Things to watch

Transfers between phones vary by manufacturer. iPhones can transfer eSIMs between devices smoothly; on some Android models you’ll need the network to reissue the profile.
Don’t delete an eSIM profile unless you’re sure — restoring it usually means contacting the network.
Smartwatches with mobile data use their own eSIM add-on plan; that’s separate from your phone’s eSIM.

→ Use the fix mobile signal diagnostic

eSIM in the UK: how it works, how to set it up, and why it helps