What is a data only SIM?
A data only SIM is a SIM card that gives you mobile internet access with no calls or texts attached, built for tablets, laptops, mobile wifi hotspots and, increasingly, smartwatches. You slot it into a device that has its own SIM tray or eSIM profile, top up with a data plan, and you’re online wherever there’s a signal, no wifi router needed.
It’s not a new idea. What’s changed is how many of us now own a second or third connected gadget sitting idle because nobody thought to give it its own connection. A tablet you only use on the sofa. A laptop that only gets online through your phone’s hotspot, draining both batteries. That’s the gap a data only SIM quietly fills.
Why is demand for a data only SIM rising in 2026?
Demand is rising because more of us now carry more than one connected device, and Ofcom’s own figures back that up. Dedicated mobile broadband subscriptions in the UK reached 5.2 million by the end of Q1 2026, up 421,000 (8.8%) on the year before, according to Ofcom’s telecommunications market data (checked August 2026).
Some of that growth is back to school and university season, with laptops and tablets needing their own connection away from home wifi. Smartwatches account for another chunk, increasingly wanting a data link that doesn’t depend on your phone being nearby. None of it’s a coincidence. It’s the sort of quiet, sensible switch that never comes up while everyone’s busy arguing about the latest handset.
What does a data only SIM typically cost?
Prices vary a fair bit by network and data allowance, so treat any figure here as a rough guide rather than a promise. Rolling monthly data only SIMs from providers like SMARTY have offered tiers around 2GB, 15GB, 40GB and 100GB, plus an unlimited option, with no fixed contract and the ability to pause or change your plan whenever you like (checked August 2026).
That flexibility matters more than the headline price. If your tablet only leaves the house twice a month, a small rolling allowance you can pause beats a cheap looking 12 month contract you’re locked into regardless. Roaming needs a glance too. Some data only SIMs include an EU data allowance of up to around 12GB before extra charges kick in, though this varies by provider and can change, so check the current terms before you travel (checked August 2026).
Key things to check before you buy
- Rolling monthly versus a fixed term, so you’re not stuck paying for a tablet you barely use.
- Whether the SIM size matches your device, or whether it supports eSIM instead.
- Network coverage in the specific spots you’ll actually use the device.
- Any EU roaming allowance, if you’re likely to travel with the device.
- Whether you can top up or downgrade the data allowance without penalty.
Data only SIM or a smartwatch pairing plan?
If the device in question is a smartwatch, a standalone data only SIM isn’t always the neatest fit, and some networks offer an alternative. Three’s Smartwatch Pairing Plans add roughly £1.80 a month to share your existing phone allowance with your watch, rather than buying it a separate connection (checked August 2026). Vodafone’s OneNumber Connectivity Plan works on a similar principle, letting your smartwatch or an eSIM enabled tablet share the airtime and data you already pay for on your main plan (checked August 2026).
For a tablet, laptop or mobile wifi dongle that lives away from your phone, a proper data only SIM tends to make more sense, since it isn’t tied to your handset’s plan or its battery. Compare both routes before you commit. The cheaper option depends entirely on how you actually use the second device, not on which one sounds neater.
Roo, Switcheroo’s resident optimist, likes to point out that most of us are paying for connectivity we’ve already forgotten we own. A five minute check on your existing plan usually confirms it.
If you’d rather sort your main handset’s SIM only plan while you’re at it, our guide to SIM only versus phone contracts is a good next stop, and if you’re weighing up whether you even need unlimited data on any of your devices, we’ve covered that in our guide to unlimited data SIMs too.
How do you fit a data only SIM without wasting money?
You avoid wasting money by matching the SIM’s data allowance to how the device is actually used, not to how you imagine you’ll use it. A tablet for reading on the train needs a fraction of the data a laptop doing video calls on the move would chew through in a week.
Check too whether your existing phone plan already lets you add a second SIM to the same account. Our guide to dual SIM phones covers a related route, splitting one phone across two numbers or plans, which for some people is a simpler fix than buying a whole separate data only SIM. And if a new handset is part of the plan anyway, our full mobile phone deals page is a decent starting point before you commit either way.
Frequently asked questions about data only SIMs
- Can I use a data only SIM in a normal phone?
- Physically yes, if the size fits, but you won’t be able to make calls or send texts on it, only use data, so it only really suits a phone you’re repurposing as a hotspot or camera.
- Do data only SIMs come with a contract?
- Many are rolling monthly with no fixed term, so you can cancel or change the data allowance whenever you like, though some providers also offer longer fixed term deals at a lower monthly cost, so compare both before you decide.
- Will a data only SIM work in my smartwatch?
- Some will, but many smartwatches are designed to pair with your existing phone number instead through a network’s own connectivity plan, so check your watch’s specification before you buy a separate data only SIM.
- Do data only SIMs work abroad?
- Some include an EU roaming allowance as part of the plan, but this varies by provider and can be capped, so check the current terms before you travel rather than assuming your UK allowance carries over in full.
- Is a data only SIM cheaper than adding a device to my phone contract?
- It depends on how much data the device needs and how long you’ll use it for, so there’s no fixed answer, but a rolling data only SIM you can pause tends to suit occasional use better than a long, fixed add on.
