What is an eSIM?
An eSIM (embedded SIM) is a programmable SIM built directly into your phone's circuit board. Instead of inserting a physical plastic card, you activate a network by scanning a QR code or entering an activation code. The result is the same — a live mobile connection — but eSIMs can be switched remotely, stored in multiples, and can't be lost or damaged.
All four major UK networks and most MVNOs now support eSIM to some degree, though the level of support varies — particularly for pay-as-you-go customers.
Which UK networks offer eSIM?
eSIM vs physical SIM: does coverage differ?
No. An eSIM connects to exactly the same masts and uses exactly the same spectrum as a physical SIM from the same operator. Your coverage is entirely determined by which network you choose — not whether you use a physical card or an eSIM. If you're evaluating networks for coverage, check your postcode and compare the networks rather than the SIM format.
Do all phones support eSIM?
Most flagship smartphones from 2019 onwards support eSIM, including all iPhone models from XS onwards, Google Pixel 3 and later, and most Samsung Galaxy S-series from the S20. Mid-range and budget handsets are inconsistent — check your specific model's specifications. Note that some phones sold by networks are eSIM-locked and can only be activated with that carrier's eSIM profiles until unlocked.
eSIM for travellers
One of the biggest practical advantages of eSIM is travel. With dual-SIM support, you can keep your UK number active while adding a local data eSIM in any country — avoiding roaming charges without carrying a second phone. This is a separate use case from choosing a UK domestic plan.
Frequently asked questions
Can I have both a physical SIM and an eSIM on the same phone?
Most modern iPhones and Android flagships support dual SIM (one physical, one eSIM) or even dual eSIM. This lets you run a UK number alongside a travel eSIM abroad, or keep a personal and work number on the same device.
Does an eSIM affect coverage or signal strength?
No. An eSIM uses exactly the same network infrastructure as a physical SIM on the same operator. Your coverage is determined by which network you're on — not the type of SIM.
Can I transfer my existing number to an eSIM?
Yes. Request a PAC code (text PAC to 65075) from your current provider and use it to port your number to an eSIM plan on your new network — or ask your existing network to reissue your number as an eSIM if they support it.