Mobile · Deals checked today
100GB SIM-only deals and bigger, compared
The quick answer
The best-value SIM-only deal we found on 27 Oct 2026 is Talkmobile 100GB 12 months at a real cost of £8.71 a month (100GB data · Vodafone network · 12 months). The table ranks 51 deals from 19 providers by real cost, with fees and stated price rises included. Most data for your money: VOXI £20 plan (3x data offer) works out at £0.07 per GB a month.
Cheapest 100GB+Affiliate
Talkmobile
100GB 12 months
100GB data · Vodafone network · 12 months
Real cost
£8.71/mo
£104.49 over
12 months
51 deals · best value first
The deals, ranked by what you really pay
AffiliateRanked by real cost: setup fees and every stated price rise in, reward cards out. Prices checked on each provider's own site, 27 Oct 2026.
Why our prices are different
The real cost, worked out for you
The headline price is only the start. We add every fee and every price rise the provider states, take off any reward, and share it across the contract. Here is today's Talkmobile 100GB 12 months.
How we rank every deal£4.98 a month × 12
£59.76
The price they advertise
Setup fee
£0.00
None on this deal
Stated price rises
£44.73
Every rise they publish, in pounds
Reward card
£0.00
None on this deal
= Real cost
£104.49 over 12 months
£8.71 a month
Who needs 100GB a month
Choose 100GB a month if you stream video often, share your phone's data or have no home broadband.
Streaming films, sport and music on your phone uses data quickly. If you watch every evening, a big allowance stops you running out early.
Hotspotting means sharing your phone's data with a laptop or tablet. Working on a laptop away from home can use a lot of data fast.
Without home broadband, your phone is your main connection, so a bigger allowance matters more.
Not sure how much you use? Check last month's data use in your phone's settings. Then try our mobile data calculator to see which allowance fits.
100GB or unlimited?
Compare real cost, not the word unlimited. A capped 100GB plan wins when its real cost is lower than an unlimited plan's. Real cost counts every stated price rise and setup fee, minus any reward card or bill credit, averaged over the contract.
A 30-day SIM lets you leave with a month's notice or less. A 12 or 24-month plan is cheaper up front but ties you in. Choose the length you can commit to.
Start at the top of the table, which ranks deals by real cost. Then compare the top options with unlimited data SIMs before you decide.
Switch and keep your number
Yes, you can keep your number when you switch mobile network. The process starts with one text.
- Text PAC to 65075 to get your PAC code.
- Give that code to your new network when you sign up.
- Your number moves in one working day.
Leaving without keeping your number? Text STAC to 75075 instead.
Before you choose, compare the cheapest deals so you know which network to join.
Straight answers
Questions people ask
- Is 100GB of data enough for a month?
- Yes, if your phone's data use last month came in under 100GB. Check the figure in your phone's settings. A 30-day SIM rolls month to month, so you can leave with a month's notice or less if you run short. Contracts agreed online or by phone also come with a 14-day cooling-off period in which you can cancel.
- Is unlimited cheaper than 100GB?
- No, not automatically. Each plan is ranked by real cost: everything you pay over the contract, averaged per month. Compare the monthly price, any stated price rise and any setup fee, and the lowest real cost wins in our table.
- Can I use a 100GB SIM as home broadband?
- Yes, if your address gets a strong signal on the network your SIM uses. Every UK SIM-only brand runs on EE, O2, Vodafone or Three, and brands on the same network share its coverage. A 30-day SIM lets you test your home signal, then leave with a month's notice or less.
Keep comparing
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