An eSIM is a digital SIM built into your phone, tablet, or smartwatch that does the same job as a physical SIM card without needing a tiny piece of plastic.
Instead of swapping cards, you activate a mobile plan by scanning a QR code or using your network's app, and the details are stored securely on the embedded chip. Most phones made since 2018 support eSIM, and all major UK networks now offer eSIM plans.
Key takeaways
- An eSIM is a digital SIM soldered into your device: no physical card needed.
- Activate by scanning a QR code or through your network's app.
- You can store multiple eSIM profiles and switch between them in settings.
- Dual SIM (one physical + one eSIM, or two eSIMs) lets you run two numbers.
- Ideal for travel: buy a local data plan abroad without swapping SIMs.
How Does an eSIM Work?
When you buy an eSIM plan, your network sends your subscriber details over the internet instead of on a plastic card. You add them by scanning a QR code, tapping a link, or entering details manually in your phone's mobile data settings.
The phone stores the profile on its embedded SIM chip and connects to the network exactly like a physical SIM. Switching networks is just a matter of downloading a new profile, with no waiting for post.
Which Phones Support eSIM?
Apple added eSIM support with the iPhone XS in 2018, and every iPhone since, including all recent models, supports it; some US models are eSIM-only. Samsung Galaxy flagships, Google Pixel phones, and many Motorola and Honor devices also include eSIM.
Most smartwatches with cellular, such as the Apple Watch, use eSIM too. Check your phone's settings under mobile data: if you see an "add eSIM" option, your device supports it.
eSIM vs Physical SIM: Pros and Cons
The big wins are instant activation, no lost or damaged cards, and multiple profiles on one device. Dual SIM is easier: keep your UK number active while using a travel eSIM for data abroad.
The downsides: moving your number to a new phone takes a few taps rather than a straight card swap, and a handful of smaller MVNOs still do not support eSIM. Very old phones lack the hardware entirely.
Using an eSIM for Travel
Travel is where eSIM shines. Before a trip, buy a travel eSIM data plan from providers such as Airalo or your own network's roaming add-on, install it over Wi-Fi, and land with data working immediately.
It is usually far cheaper than standard roaming charges, and you keep your UK number active for calls and texts on your main SIM. Just make sure data roaming is enabled for the travel eSIM and disabled for your home SIM to avoid surprise bills.
How to Set Up an eSIM in the UK
All four major UK networks (EE, O2, Vodafone, and Three) support eSIM on pay-monthly plans, and most now offer it on PAYG too.
Order the plan, then follow the QR code or app instructions: on iPhone go to Settings > Mobile Service > Add eSIM, on Android look under Network & Internet > SIMs. If you are switching networks, request a PAC code to keep your number, then activate the new eSIM when the transfer completes.
FAQ
What is an eSIM in simple terms?
An eSIM is a digital SIM built into your phone. It stores your network plan electronically, so there is no physical card to insert or swap.
How do I activate an eSIM?
Scan the QR code from your network, use their app, or enter the details manually in your phone's mobile data settings. It usually takes a few minutes.
Can I use eSIM and a physical SIM at the same time?
Yes. Most phones support dual SIM, letting you run two numbers at once, for example work and personal, or home and travel eSIM.
Is eSIM better than a physical SIM?
For most people, yes: instant activation, multiple profiles, and easy travel use. The only real drawback is that moving phones takes a couple of extra steps.
Do all UK networks support eSIM?
EE, O2, Vodafone, and Three all support eSIM. Support among smaller MVNOs varies, so check before signing up.
Can I use an eSIM when travelling abroad?
Yes, and it is often the cheapest option. Buy a travel eSIM before you fly and you will have data the moment you land, while keeping your UK number active.
