5G SIM started in 2018, when 5G in the UK was mostly slide decks and spectrum auctions. Back then the questions were simple: when will it arrive, and will my SIM work? In 2026 the questions are better. Which kind of 5G am I on? Why does my router say 5G but behave like 4G? Should my IoT fleet use a roaming SIM, a multi-network SIM or eSIM? Will any of this survive the 2G switch-off?
This site exists to answer those questions properly, in plain English, for people who have to make connectivity work.
Who writes it
5G SIM is written and edited by Nick Appleby.
Nick has worked in UK telecoms and mobile data for more than 25 years, from ADSL and early M2M modems through to 4G and 5G cellular routers, IoT SIMs and eSIM. Most of that time has been spent on the practical side: getting connections working in awkward places and working out why they dropped.
He is interested in the part most coverage skips: what happens between the SIM, the mast and the core network, and why the same 5G icon can mean very different things depending on who sold you the SIM.
What you will find here
- Guides that explain how UK 5G works and are reviewed as things change. Start with UK 5G networks.
- The notebook, which is where hardware notes, product write-ups and news live. Some notebook posts are older and reflect the market at the time they were written; each shows its date.
- A glossary for the acronyms.
How it is written
Facts about networks come from operator announcements and Ofcom reporting, and the guides say when figures were checked. Operator coverage claims are reported as claims, with Ofcom’s independent figures alongside where they exist. Nobody pays to appear in the guides. The full approach is in the editorial policy.