EID stands for eSIM Identifier (sometimes Embedded Identity Document). It's a unique 32-digit number burnt into every eSIM chip at manufacture, similar to how every phone has an IMEI.
How to find your EID
Dial *#06# on most phones — the EID appears alongside your IMEI. On iPhone: Settings → General → About. On Android: Settings → About phone → SIM status.
Why it matters
Carriers use your EID to provision an eSIM profile specifically to your device. If you change phones, the EID changes, and you'll need to re-provision your eSIM on the new device.
See also
How EID matters when picking a UK mobile plan
Understanding EID 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 EID 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.