Not everyone needs unlimited data. If your phone is connected to Wi-Fi at home and at work, you use mobile data mainly for maps, messaging and the occasional browse, you could be overpaying significantly for a plan designed for heavy streamers.
This guide is for people who use under 10GB of mobile data per month and want to pay as little as possible. Below you will find the cheapest current deals in that range, pulled live from our database.
Cheapest SIM only deals under 10GB right now
How much data do you actually need?
The easiest way to find out is to check your current usage. On iPhone, go to Settings → Mobile Data and scroll down to see per-app usage. On Android, go to Settings → Network → Data usage. This shows you exactly how much you have used over the current billing period.
| Usage type | Monthly data | Typical habits |
|---|---|---|
| Light | 1–3GB | Mostly on Wi-Fi, occasional maps and messaging |
| Moderate | 3–7GB | Social media browsing, some music streaming |
| Regular | 7–10GB | Regular social media, video clips, working on the go |
| Heavy | 10GB+ | Video streaming on data, minimal Wi-Fi reliance |
If you use more than 10GB per month, compare unlimited SIM only deals — unlimited plans are often only a few pounds more and remove the risk of hitting your cap.
Why choose a low data plan?
The main reason is cost. The cheapest SIM only plans in the UK are in the 1–5GB range — often under £5 per month — and offer genuine value for users who do not need large allowances. There is no benefit to paying for data you will not use.
If you are worried about occasionally underestimating your usage, look for plans with data rollover. Both Smarty and giffgaff credit unused data back as account balance, so months where you use less reduce your next bill. This acts as a buffer if your usage varies.
Frequently asked questions
What happens if I go over my data allowance?
Most networks will either stop your mobile data until your next billing cycle or charge you for additional data at a rate set out in your plan's terms. Some networks — like giffgaff — allow you to top up mid-month. To avoid surprise charges, enable data usage alerts in your phone's settings and check your network's overage policy before signing up.
Can I change my data allowance later?
On 30-day rolling SIM only plans, yes — you can switch to a higher (or lower) data tier at the end of each month with no penalty. This is one of the main advantages of monthly rolling plans over 12 or 24-month contracts, where you are locked into your chosen allowance for the duration of the term.
Is 5GB enough for a smartphone?
For most Wi-Fi-heavy users, yes. 5GB comfortably covers checking emails, browsing social media, using Google Maps and occasional YouTube clips when out and about. According to Ofcom, the median UK mobile user consumes around 6–8GB per month — but this includes people who stream video on mobile data regularly. If your phone is connected to Wi-Fi most of the time, 3–5GB is typically sufficient.
Deals shown are pulled live from our database and update daily. We may earn commission when you click through — this never affects our editorial rankings or recommendations.