An eSIM (embedded SIM) is a SIM card that's built into your phone instead of being a removable piece of plastic. Rather than posting you a card, your network sends you a digital SIM profile — usually a QR code — and you're connected in minutes.
The short answer
An eSIM does everything a normal SIM does — your number, calls, texts and data — but it's downloaded to your phone rather than inserted. If your phone supports it, you can activate a Giffgaff or Lebara eSIM instantly instead of waiting 3-5 days for a plastic SIM in the post.
How does an eSIM work?
Your phone has a small chip soldered inside — the "embedded" part. When you buy a plan, your network generates a SIM profile for that chip. You install it one of three ways:
- QR code: scan a code in your phone's settings — the profile downloads and activates.
- Network app: networks like Giffgaff and Lebara can push the eSIM straight from their app.
- Quick transfer: moving iPhone to iPhone (or some Androids), the eSIM can transfer directly between phones.
Which phones support eSIM?
Most phones made since 2020 have eSIM built in:
- iPhone: XS, XR and every model since (iPhone 14 onwards in the US is eSIM-only — no SIM slot at all)
- Samsung: Galaxy S20 onwards, plus Z Flip/Fold models
- Google Pixel: Pixel 3 onwards
- Others: recent Motorola, Oppo, Xiaomi and Huawei flagships
Quick check: on iPhone go to Settings → Mobile Service and look for "Add eSIM". On Android look under Settings → Network & Internet → SIMs for a download/add option.
eSIM vs physical SIM: which is better?
- Instant activation: no waiting for the post — be connected in minutes.
- Can't lose it: nothing to drop, damage or get stolen with your phone's SIM tray.
- Dual SIM: run two numbers on one phone — work + personal, or UK + local SIM abroad.
- Easy switching: changing networks is a download, not a new card.
- The catch: moving an eSIM between phones takes a few steps in settings, rather than just swapping a card. And your phone must support it.
Do Giffgaff and Lebara offer eSIM?
Yes — both networks now support eSIM on compatible phones:
- Giffgaff: activate an eSIM through the giffgaff app or website. Existing customers can swap a physical SIM to eSIM in their account settings. Still free to join, still £5 bonus credit on activation with a £10 top-up via our link.
- Lebara: eSIM available through the Lebara app — ideal if you want to be live on the Vodafone network within minutes rather than days.
Who should use an eSIM?
- Anyone in a hurry — instant activation beats waiting for post.
- Dual-SIM users — keep work and personal numbers on one device.
- Travellers — add a local data eSIM abroad while your UK SIM stays active for calls and texts. See our EU roaming guide for cheaper alternatives.
- Switchers — test a new network on eSIM alongside your current SIM before committing.
Can I keep my number on an eSIM?
Yes — your number isn't tied to the plastic. Text PAC to 65075 from your current SIM, give the code to your new network during eSIM setup, and your number transfers within about one working day. Full steps in our keep your number guide.
Try an eSIM free
Giffgaff and Lebara both support eSIM — be connected on O2 or Vodafone's network within minutes.