An eSIM QR code is the activation token a carrier sends you when you sign up. It encodes the address of the carrier's provisioning server (SM-DP+) and an activation token specific to your line. Your phone scans it, downloads the eSIM profile, and you're connected.
How activation works
- Carrier sends you a QR code (usually by email)
- On iPhone: open Camera, point at the code, tap the notification. On Android: Settings → eSIM → Add eSIM → Scan QR
- Phone contacts the SM-DP+ server using the address in the QR
- Server sends down the eSIM profile (about 1 MB)
- Phone stores it on the eSIM chip and activates
The whole process takes 2-3 minutes from scan to working signal.
Security
QR codes are single-use. Once your phone has consumed a code, the activation token is invalidated — nobody else can use the same code to activate on a different device.
See also
How eSIM QR Code matters when picking a UK mobile plan
Understanding eSIM QR Code helps you compare mobile providers on a like-for-like basis. Most consumer mobile pricing pages skip the technical detail — knowing the terminology means you can spot when a plan is genuinely better and when it just sounds that way. The Fuse Mobile glossary keeps definitions short and consumer-focused, no jargon-on-jargon.
Fuse Mobile is a UK multi-network data-only eSIM — it gives your phone access to all four UK mobile networks (EE, Three, Vodafone, O2) through a single profile. Where eSIM QR Code is relevant to that setup, it's surfaced explicitly: pricing pages show real numbers, the coverage checker shows live per-network signal, and there's no hidden fee structure. See the plans page for the current pricing or read the multi-network eSIM explainer for the technical detail.