SIM only plans have just become half of all UK pay-monthly subscriptions, according to Ofcom, and the usual advice says the other half is overpaying. On average, that is true. Ofcom priced an iPhone 17 at £799 to buy outright, yet found people acquiring one through a 24-month contract paid an average of £999 for the same phone. Then we ran the numbers on our own comparison, and the cheapest phone contracts in the feed beat buying the handset yourself. Both things are true at once, which is exactly why this decision deserves ten minutes. Here is when each route wins, what happens at the end of each kind of contract, and the trap that costs bundled-contract customers around £11 a month.
The average says SIM only wins
Ofcom's February 2026 pricing research compared buying a handset and airtime together against buying the phone outright and pairing it with a SIM only plan. Buying separately was cheaper in every case it tested, by an average of £10.54 a month, with savings running from 15 to 50 percent. On the iPhone 17 the premium ranged from £23 to £428 depending on the provider, and for one brand it worked out like taking a 47 percent APR loan for the phone, worse than most credit cards.
The reasons stack up quickly. A contract bakes the handset into a monthly price you keep paying in full for the whole term. Airtime on big-network contracts usually carries scheduled April rises. And the plans sold alongside flagships tend to be big ones: Ofcom found 39 percent of pay-monthly customers take over 50GB a month, while only 5 percent use that much. Paying £2 a month for data you never touch is not a rounding error over 24 months, it is £48.
When a contract genuinely wins
Averages hide the deals. On 29 August 2026 we pulled every pay monthly phone deal on Switchity and worked out the true 24-month cost of the cheapest contract for three current flagships, scheduled price rises included. Then we compared each against buying the same phone from its maker's own UK store with the cheapest matching SIM alongside. That SIM is iD Mobile's 20GB plan at £6.00 a month with no rises, £144 over the two years.
| Handset | Cheapest contract, 24-month total | Buy it yourself, plus SIM only |
|---|---|---|
| iPhone 17 256GB | £815.80 (15GB plan, £529 upfront, no rises). | £943.00 (£799 phone plus £144 of SIM). |
| Galaxy S26 256GB | £641.80 (15GB plan, £355 upfront, no rises). | £923.00 (£779 phone plus £144 of SIM). |
| Pixel 10 128GB | £511.80 (15GB plan, £225 upfront, no rises). | £843.00 (£699 phone plus £144 of SIM). |
Source: the Switchity deal feed plus Apple, Samsung and Google's own UK store prices, checked 29 August 2026. Contract totals include upfront costs and every scheduled mid-contract rise. The Galaxy figure uses Samsung's store price on the day; its list price is £879.
Read that twice, because it cuts against the received wisdom: on the day we checked, the cheapest contract beat buying the phone yourself on all three handsets, by £127 to £331. The catch is the word cheapest. These are retailer-discounted deals with 15GB allowances and chunky upfront payments, not the network-direct prices Ofcom averaged, and offers like this churn weekly. Move up to unlimited data and the contract route costs £100 to £160 more, which hands the advantage straight back to SIM only. The lesson is not that contracts are secretly cheap. It is that neither route wins by default, so run the total both ways before you sign anything.
One agreement or two? The question that decides the end game
Before comparing prices, check what kind of contract you are being offered, because UK phone contracts now come in two shapes. Ofcom puts it plainly: most providers have stopped selling combined contracts and now sell split ones.
A split contract is two agreements. The airtime plan covers your data, calls and texts, and the phone sits on a separate interest-free loan, a real credit agreement regulated by the Financial Conduct Authority. O2's Refresh, Vodafone's EVO, Sky Mobile's device loans, Tesco Mobile's Anytime Upgrade Flex and EE's Flex Pay all work this way, with loan terms running from 12 months up to 48 on EE. A bundled contract is one agreement with one monthly price covering both, which is how Three and iD Mobile sell phones, and how the retailer deals in our comparison are built.
The difference sounds bureaucratic until the contract ends.
What happens when the minimum term ends
Here is the money question nobody asks in the shop. Ofcom found 41 percent of pay-monthly users are out of contract, and what happens to their bills depends entirely on which shape of contract they signed. On a split contract the loan simply finishes: the device payments stop, and you keep paying for airtime only. On a bundled contract, nothing happens. The full monthly price, handset share included, rolls on until you act.
| Network | What happens after the minimum term |
|---|---|
| O2 | "We automatically lower your bill once you've paid off your device," per its own plans page. |
| Vodafone | EVO's page says that once the phone plan is paid off, "your monthly payment will be lower". |
| Tesco Mobile | "Once your phone's paid off you can either drop down to just your monthly data plan payments, or decide to upgrade". |
| EE | Flex Pay device payments sit on their own agreement with their own Direct Debit; they simply finish, and the airtime plan carries on separately. |
| Sky Mobile | The phone loan is a fixed set of 0 percent instalments that runs separately from the data plan; when the instalments end, only the data plan continues. |
| Three | Its terms contain no price reduction after the minimum term; the bundled price continues until you cancel or upgrade. |
| iD Mobile | Its published terms describe one agreement that continues on the same terms until you give 30 days' notice. |
Source: each network's own pages and published terms, checked 29 August 2026.
This is not a small leak. Back in 2019, Ofcom found 1.4 million out-of-contract bundled customers overpaying by an average of just under £11 a month. Most networks then committed to end-of-contract discounts from February 2020, while Three declined to apply any, and no newer Ofcom statement has revisited those commitments since. Every network must also send you an end-of-contract notification with its best deals before your term ends, a rule in force since 15 February 2020. The letters arrive. The overpaying continues anyway, because the default is doing nothing, and on a bundled contract doing nothing means paying phone money for a phone you already own.
The rest of the scorecard
Price is the headline, but four quieter differences decide how the deal feels a year in.
- Flexibility costs almost nothing now. In our feed the cheapest 30-day rolling SIM at 30GB or more is £7.00 a month, and so is the cheapest 12-month deal. Committing for a year once bought a real discount; today the rolling plan's freedom is close to free.
- Price rises follow the contract type. 241 of the 407 SIM only deals on Switchity carry no scheduled rise at all, and a 30-day deal can always be left before a rise bites. Big-network contract airtime mostly carries fixed April increases; our price rises guide lists them network by network.
- Credit checks scale with the borrowing. A rolling SIM involves little or no credit checking, a 12-month SIM a light one, and a phone contract a full one, because the device half is a loan. If a phone-contract application is declined, a 30-day SIM plus a cheaper handset is the standard route back.
- Mid-term control varies. O2 lets you change your data allowance every month, Vodafone's EVO airtime can be moved up mid-term but not down, and a bundled price is fixed for the term. Check your allowance against reality before you pick any plan: Ofcom found 55 percent of pay-monthly customers use a fifth or less of their data, and our data guide shows how to measure yours.
And on the SIM side, this is what the market costs this week:
| Data allowance | Cheapest deal | Typical price | Deals |
|---|---|---|---|
| Up to 3GB | £2.90 a month (1GB, Spusu) | £6 | 11 |
| 3 to 10GB | £3.80 a month (3GB, Mozillion) | £7 | 26 |
| 10 to 20GB | £5.90 a month (10GB, Spusu) | £7 | 37 |
| 20 to 50GB | £5.95 a month (20GB, TalkMobile) | £10 | 67 |
| 50 to 100GB | £7 a month (50GB, iD Mobile) | £10 | 81 |
| 100GB+ | £8.95 a month (100GB, TalkMobile) | £15 | 125 |
| Unlimited | £14 a month (unlimited, giffgaff) | £22.50 | 60 |
“Typical price” is the median monthly price in the band. Click a band to see every deal in it. Prices change as networks refresh their offers; the checked date above is when this table was last rebuilt.
Want a new phone without a phone contract?
A network contract is no longer the only way to spread a phone's cost. Apple and Google sell their phones on 0 percent instalments direct from their own stores. giffgaff sells new and refurbished handsets on Klarna loans that sit apart from its plans, and VOXI finances phones through PayPal Credit with no VOXI plan attached. The refurbished market pairs a year-old flagship with any SIM in the table above for hundreds less than new. Each of these keeps your airtime free to be the cheapest SIM you can find, which is the whole trick.
The practical takeaway
If your phone still works, SIM only wins and it is not close: the median SIM on Switchity is £12.00 a month, and a good 20GB plan is £6.00. If you want a new flagship, refuse to default either way; put the contract's full-term total against the maker's store price plus 24 months of SIM, the way our table does, and let the arithmetic decide. If you are on a bundled phone contract past its end date, you are the £11-a-month statistic, and moving to SIM only today is the quickest saving in mobile. And if you are mid-contract and tempted, the maths of leaving early lives in our exit fee calculator and exit fees guide: sometimes paying the fee still wins.