- Status
- Updated daily
- Total deals tracked
- 542
- Networks tracked
- 21
- Last snapshot
- 10 Sep 2026
Written by Phil Brown
Founder, SIM Only Finder. Former Three UK retail manager with more than a decade building consumer comparison platforms. About Phil Brown
What the SIM Only Price Index tracks
The SIM Only Price Index draws on live deal data collected by SIM Only Finder across 21 UK networks and MVNOs. Every deal listed on the site feeds into the index, giving us a dataset that reflects actual available prices rather than advertised headline rates.
We track average monthly cost by data allowance tier across all contract lengths: 30-day rolling, 12-month, and 24-month. Prices are sourced directly from network and MVNO listings and the index is updated daily.
The index began tracking daily snapshots in April 2026. Historical month-by-month data will build automatically from that point.
Average SIM only prices by contract length
Compare average prices across different contract lengths.
| Data tier | Average | Lowest | Highest | Deals |
|---|---|---|---|---|
| Under 10GB | £8.54 | £2.90 | £30.00 | 36 |
| 10GB - 50GB | £11.37 | £5.90 | £33.00 | 52 |
| 50GB - 100GB | £12.37 | £7.00 | £35.00 | 36 |
| 100GB - unlimited | £17.48 | £8.95 | £37.00 | 49 |
| Unlimited | £26.52 | £15.00 | £47.00 | 26 |
| Data tier | Average | Lowest | Highest | Deals |
|---|---|---|---|---|
| Under 10GB | £11.61 | £4.50 | £27.99 | 14 |
| 10GB - 50GB | £10.94 | £5.95 | £30.99 | 51 |
| 50GB - 100GB | £10.59 | £7.95 | £23.00 | 52 |
| 100GB - unlimited | £15.80 | £9.95 | £34.99 | 59 |
| Unlimited | £22.46 | £14.00 | £41.99 | 24 |
| Data tier | Average | Lowest | Highest | Deals |
|---|---|---|---|---|
| Under 10GB | £14.31 | £4.00 | £24.99 | 8 |
| 10GB - 50GB | £16.50 | £5.95 | £43.00 | 27 |
| 50GB - 100GB | £12.06 | £7.00 | £24.00 | 24 |
| 100GB - unlimited | £18.91 | £10.00 | £47.00 | 57 |
| Unlimited | £27.44 | £15.00 | £56.00 | 27 |
Which networks have raised prices
Mid-contract price rises are now a standard feature of the UK mobile market. O2 applied a rise of up to £2.50 per month in April 2026, the largest we have tracked from a major network since Ofcom tightened its mid-contract guidance. Customers on O2 rolling contracts can switch without penalty.
How to use this data to find a better deal
If your current monthly cost is above the average for your data tier and contract length shown above, you are likely overpaying relative to what is currently available on the market.
The quickest way to act on that is to check whether you are on a rolling 30-day contract or a fixed term. If you are on a rolling contract, you can switch at any time with no exit fees. If you are on a fixed-term plan and your network has applied a mid-contract price rise, you have the right to exit without penalty within 30 days of being notified. Our PAC code guide explains how to keep your existing number when switching networks.
Editorial policy
Phil Brown, founder of SIM Only Finder, writes and maintains this page using live deal data collected across 21 UK networks and MVNOs. Pricing data is sourced directly from network and MVNO listings and updated daily. Phil's monthly commentary reflects his own analysis based on his experience in the UK mobile industry. Always confirm current pricing directly with your chosen network before signing up.
Ofcom-accredited price comparison
SIM Only Finder is accredited by Ofcom, the UK's independent regulator for communications services. Accreditation is awarded to comparison sites that meet Ofcom's standards for accuracy, transparency, and impartiality.
This means the deals you compare here are checked for accuracy, presented without bias toward any network, and reflect the actual cost you would pay. We do not promote deals based on commission earned.
Phil Brown's commentary
Phil Brown
August 2026
The broad rise we reported last month has not continued. Prices moved in both directions this month, with eight of the fifteen figures we track falling, which suggests July was a one month correction rather than the start of a sustained climb.
The clearer pattern is a split between rolling and committed contracts. Rolling plans got cheaper in four of the five tiers, with 100GB to unlimited down from £18.13 to £17.48 and 50GB to 100GB down to £12.37. Longer contracts moved the other way at the small end, with under 10GB rising to £11.61 on 12 months and £14.31 on 24. If you use a modest amount of data, a rolling plan currently averages £8.54 and there is no financial case at all for committing.
That 24-month figure deserves attention. Under 10GB on a two year contract has risen every month since we launched the index in April, from £10.50 then to £14.31 now. It has passed the 24-month average for 50GB to 100GB, which sits at £12.06. In other words, the market will currently sell you five times the data for less money on the same contract length. We track a small number of deals in that tier so the average is more volatile than others, but the direction has been consistent for five months and the gap is too wide to be noise.
For anyone buying on value, 50GB to 100GB remains the sweet spot it has been all year. At £10.59 on a 12-month plan it is cheaper than an under 10GB plan on the same term. Unlimited is also worth buying on 12 months rather than either alternative, at £22.46 against £26.52 rolling and £27.44 over two years.
Phil Brown
July 2026
Prices have risen across almost every tier and contract length this month, which is the first broad move upwards since the index launched in April. The 50GB to 100GB tier, which softened for three consecutive months, has ticked back up to £12.70 on 30-day rolling and £10.43 on 12-month. The falls we reported through spring appear to have bottomed out.
The clearest finding this month is that committing for two years now costs you more than committing for one. A 12-month plan is the cheapest option in four of the five tiers we track, and 24-month is the most expensive in four of them. The gap is widest in the 10GB to 50GB tier, at £10.74 on 12 months against £15.61 on 24, though the number of 24-month deals in that tier is small enough that the figure may reflect which plans are currently listed rather than a change in what networks charge. The pattern holds across the other tiers regardless. If you are being offered a two-year contract on the basis that longer means cheaper, check that claim against a 12-month equivalent before signing.
At the small end, rolling plans remain the cheapest way to buy. Under 10GB averages £8.68 on 30-day rolling against £10.44 on 12 months and £12.45 on 24. For light users there is currently no financial argument for tying yourself in at all.
Unlimited has moved up across the board, with the 30-day average now £26.17. That said, 12-month unlimited at £22.82 is more than £3 cheaper than either alternative, and the 24-month average of £26.73 is now above the rolling price, which makes a two-year unlimited commitment difficult to justify.
Phil Brown
June 2026
The 50GB to 100GB tier has now softened for three consecutive months across all contract lengths. The 30-day rolling average has dropped from £13.34 in April to £12.43 today, and the 12-month average is down to £10.27. That consistent downward movement is worth paying attention to if you are shopping in this range.
The 24-month unlimited average has fallen considerably, from £29.76 in May to £25.04. That closes the gap between 24-month and 12-month unlimited significantly and makes a two-year commitment more worth considering than it was two months ago, provided you are confident in your network choice.
The one tier moving in the opposite direction is 100GB to unlimited on 30-day rolling, which has edged up from £17.17 in April to £18.16. This is the only tier showing consistent upward pressure on rolling contracts, and it is worth comparing against the 12-month equivalent at £15.74 if you are shopping at that allowance level.
Phil Brown
May 2026
Prices have been broadly stable since April, but a few trends are worth noting. The 50GB to 100GB tier has softened across all contract lengths. The 30-day rolling average has dropped from £13.34 to £12.97, and 12-month plans in that tier now average £10.67. For anyone using moderate amounts of data, this tier continues to offer the strongest value relative to its allowance.
The 24-month 10GB to 50GB average has also fallen by over £1.50 since April, now sitting at £14.27. The flexibility premium we flagged in April remains small. In the 10GB to 100GB tiers, the saving from committing to 12 months over a rolling contract is modest, and the ability to switch without notice is worth more than the price difference suggests.
Unlimited pricing has barely moved. The 30-day rolling average of £25.65 and 12-month average of £22.46 are consistent with last month, suggesting the unlimited tier has found a floor for now.
Phil Brown
April 2026
In the under 10GB tier, 30-day rolling plans are currently cheaper on average than 12-month contracts, at £9.03 versus £10.33. That is the reverse of what you would normally expect. It reflects strong MVNO competition for flexible low-data plans and means there is little reason to commit to a 12-month deal at that allowance level right now.
O2's April rise, up to £2.50 per month, is the largest we have tracked from a major network since Ofcom tightened its mid-contract guidance. If you are on an O2 rolling plan, you can leave without penalty and there are unlimited deals available today for less than O2's post-rise price.