The short version
General information, not advice
- No calls or texts included
- Used in tablets, routers, dongles
- Available on monthly or long-term contracts
- 4G and 5G options
- Check fair usage policies
Data-only SIMs give you internet access without voice calls or texts. They go into tablets, routers and mobile broadband devices. This guide covers the contracts, allowances, speeds and roaming rules.
What a data-only SIM is
A data-only SIM provides mobile internet but carries no traditional call minutes or SMS allowance. It connects the device straight to a mobile network for data, running over 4G (LTE), 5G, and occasionally 3G, which is being phased out.
What they're used for
Data-only SIMs turn up in tablets, mobile WiFi routers (MiFi devices), 4G and 5G home broadband routers, laptops with SIM slots, security cameras, car infotainment systems and temporary office setups. They earn their place where fixed broadband isn't available or isn't reliable.
Contracts and flexibility
You'll find them as monthly rolling (30-day) contracts, 12–24 month fixed deals, and pay-as-you-go bundles. Longer terms usually cost less per month but lock you in with exit fees. Check the minimum term, early termination charges, any mid-contract price rises, and the data rollover rules.
Speed and coverage
Real-world speed depends on the network (EE, O2, Vodafone, Three), signal strength, congestion, and whether you're on 4G or 5G. In strong coverage 5G can deliver 100–500+ Mbps, but rural areas may only see 4G speeds. Check coverage maps for your area, test the signal if you can, and consider an external antenna for a fixed router.
Data limits and fair usage
Unlike home broadband, data SIMs usually come with a cap, commonly 10GB, 50GB, 100GB, or unlimited (which often has fair use rules attached). Heavy activities such as 4K streaming, downloading games and large cloud backups eat through an allowance quickly. Read the throttling policy, the fair usage limits and any speed-reduction thresholds before you rely on a plan.
Roaming
Roaming terms vary a lot since Brexit. Some providers include EU roaming, some cap roaming data, and some charge a daily fee. Before travelling, confirm which destinations are covered, what your data limit is abroad, and the out-of-bundle charges.
Key takeaways
- Ideal for portable internet
- Compare coverage maps
- Check speed caps
- Consider roaming costs
- Flexible contracts available
Common questions
Can I make calls?
Not usually, unless via apps like WhatsApp.
Is 5G available?
Yes, if your device and network support it.
Can I use a data-only SIM in my phone?
Yes, but you won't have voice call minutes unless using apps like WhatsApp.
Is a data SIM good for home broadband?
It can be, especially in areas without fibre, but speeds depend heavily on signal quality.
Does unlimited really mean unlimited?
Often yes, but fair usage policies may apply.
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