ICCID stands for Integrated Circuit Card Identifier. It's the unique serial number for a specific SIM — whether physical or eSIM. Where the EID identifies the chip itself, the ICCID identifies the carrier profile loaded onto it.
What it looks like
A 19 or 20 digit number, usually starting with 89 (the industry code for telecoms). Example: 8944501012345678901.
Why it matters
Carriers use the ICCID to bill you correctly, route calls and SMS to the right line, and identify which SIM is connecting from a given device. If you replace a faulty SIM, you get a new ICCID even though your phone number stays the same.
See also
How ICCID matters when picking a UK mobile plan
Understanding ICCID 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 ICCID 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.