Writing about UK 4G since 2012
4G data SIMs, UK networks and the routers that use them
Plain-English guides for anyone putting a SIM into a router, a camera, a vehicle or a cabinet. Which network, which plan, whether you need a fixed IP, and how to read the signal once it is installed.
UK networks at a glance
- EE · BT Group4G + 5G
- O2 · Virgin Media O24G + 5G
- Vodafone · VodafoneThree4G + 5G
- Three · VodafoneThree4G + 5G
- 3Gswitched off
- 2Gclosing by 2033
Two questions
Which kind of SIM do you need?
Guides
Start here
4G data SIM cards for routers: how to choose
Network first, then plan, then the extras. What actually matters when you put a SIM into a router.
NetworksUK 4G networks explained: EE, O2, Vodafone and Three
Four networks, dozens of brands. Who owns the masts, what changed with VodafoneThree, and why 4G is now the base layer.
Signal4G signal strength explained: RSRP, RSRQ and SINR
Ignore the bars. Three numbers tell you how good a 4G connection really is. Type yours into the checker.
RoutersChoosing a 4G router: a 10-point checklist
Bands, category, SIM slots, failover, antennas, power and management. Ten things to check before you buy.
Data SIMsFixed IP 4G SIM cards: when you need one and how they work
A fixed public IP lets you connect in to a router and the kit behind it. When that is worth it, and the alternatives.
Data SIMsIoT and multi-network SIMs: when a normal data SIM is not enough
Pooled data, more than one network, remote management and eSIM. When an IoT SIM is worth it.
Remote accessWhy can’t I reach my 4G router? CGNAT, private APNs and fixed IPs
Most SIMs sit behind carrier-grade NAT, which blocks inbound connections. The three ways round it, compared.
Signal4G antennas explained: what they do and do not do
An antenna does not boost signal. It collects it somewhere better. How to choose and fit one.
Applications4G backup broadband: keeping a business online when the line fails
Failover routers, a SIM on the right network and a test you actually run. How to keep tills, phones and cloud apps working.
Applications4G SIMs for CCTV: data, remote viewing and getting it right
CCTV is upload-heavy and needs inbound access. What that means for the SIM, the router and the data plan.
RoutersLTE categories explained: Cat 1, Cat 4, Cat 6 and beyond
The number after "Cat" on a datasheet sets the router's speed ceiling. Which one you actually need.
Routers4G or 5G: is 4G still the right choice for a router?
5G is faster, 4G is cheaper and everywhere. How to decide, and where RedCap fits.
Networks
Data SIMs by network
EE
BT Group. The UK's first 4G network, with a wide choice of business data plans.
O2
Virgin Media O2. Also carries giffgaff, Tesco Mobile and Sky Mobile.
Vodafone
Now part of VodafoneThree. Long history in M2M and IoT connectivity.
Three
Now part of VodafoneThree. Known for large data allowances on a 4G and 5G only network.
Notebook
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NAWho writes this
Nick Appleby
Nick Appleby has worked in UK telecoms since 1998, starting at BT, and has spent most of that time on cellular routers, data SIMs and the antennas that connect them for business and industrial sites. He writes 4G SIM to explain how the networks and the kit actually behave, in plain English.