How to Get the Best Deal on Your Mobile Phone Contract in the UK
Published 21st of January 2013·Updated 6 April 2026
Reviewed by: Reviewed for accuracy April 2026
The cheapest mobile phone contract is almost always a SIM-only deal paired with a phone you buy outright or already own. However, if you want a new handset, the best approach is to calculate the true cost of a bundled contract versus buying the phone separately on SIM-only. Many people overpay by hundreds of pounds simply by not comparing these two routes before signing.
Short Summary
SIM-only contracts from providers such as giffgaff, iD Mobile and Smarty routinely offer 100GB of data for under £15 per month with no long-term tie-in.
A 24-month handset contract at £40 per month costs £960 in total. If you can buy the same phone for £600 outright and run a £12 SIM-only deal, you spend £888 over two years and pay less.
Networks including EE, O2, Vodafone and Three will often offer existing customers a better renewal deal over the phone than the one advertised online, particularly if you mention a competing offer.
Your rights under Ofcom rules mean you can leave your contract penalty-free after 30 days if your provider raises the mid-contract price by more than the amount disclosed at the point of sale.
SIM-only vs handset contract: which is cheaper?
A handset contract bundles the cost of the phone into your monthly payment, which makes it feel like the phone is free. It is not. You are paying for it in instalments at an effective interest rate built into the contract price.
To work out the true cost of a handset contract, multiply the monthly cost by the number of months, then compare that total to what you would pay buying the phone outright plus a SIM-only deal for the same period.
| Option | Monthly cost | Term | Total paid |
|---|---|---|---|
| Handset contract (e.g. iPhone 15, 24 months) | £55 | 24 months | £1,320 |
| Phone bought outright + SIM-only at £12/month | £12 (SIM) + phone upfront | 24 months | £888 (phone at £600 + £288 SIM) |
| Refurbished phone + SIM-only at £10/month | £10 (SIM) + phone upfront | 24 months | £630 (phone at £390 + £240 SIM) |
In most cases, buying the phone separately works out cheaper. The exception is a zero-interest or subsidised handset deal, which some networks offer periodically.
How do I choose the right data allowance?
Buy slightly more data than you currently use, not a huge surplus. Check your current usage in your phone's settings (Settings > Mobile Data on iPhone, or Settings > Network on Android) before you choose a plan.
As a rough guide: light users who browse social media and check emails need around 5GB to 10GB per month. Regular streamers who watch video on the go need 15GB to 30GB. Heavy users who work remotely or use their phone as a hotspot regularly may need unlimited data.
Unlimited data plans from EE, O2, Vodafone and Three typically cost between £20 and £35 per month on SIM-only. They are worth considering if you regularly hit your cap and incur overage charges.
How do I negotiate a better deal at renewal?
Do not simply accept the renewal offer your network sends you. Call the retentions team directly, rather than speaking to general customer services. Retentions teams have more authority to offer discounts, free upgrades to the next data tier, or added extras such as international roaming.
Before you call, find a competing offer from another network. Websites such as Uswitch and MobilePhones.co.uk compare live deals. Tell the adviser you have found a better deal and ask whether they can match or beat it. Most networks will make an effort to keep your custom.
O2 and Vodafone both allow you to split your contract into a device plan and an airtime plan. Once the device is paid off, the monthly cost drops automatically. If your network does not offer this, check whether you are still paying the same amount after the handset cost should have been cleared, as many customers overpay for months after their handset is fully paid off.
Should I buy a refurbished phone?
A refurbished phone is a used device that has been tested, repaired where necessary, and certified to work correctly. Certified refurbished phones from retailers such as Back Market, Decluttr or directly from Apple's refurbished store typically carry a 12-month warranty and cost 20 to 40 per cent less than a new equivalent.
Pairing a refurbished iPhone 14 (around £450) with a SIM-only deal at £12 per month gives you a two-year cost of around £738. A new iPhone 14 on a 24-month contract at £45 per month costs £1,080 over the same period. The saving is over £340.
What are my rights if my network raises prices mid-contract?
Ofcom rules introduced in 2023 require mobile networks to state clearly at the point of sale how much prices may rise during your contract. If a network raises prices by more than the amount disclosed, you have the right to exit the contract without paying an early termination charge.
If your provider raises prices in line with what was disclosed (typically CPI inflation plus an additional percentage), you do not have an automatic right to leave penalty-free. In that case, you can try to negotiate, or wait until your contract ends.
FAQ
Can I keep my existing phone number when switching networks?
Yes. Ask your current network for a PAC (porting authorisation code) by texting "PAC" to 65075. Your new network will use this code to transfer your number, usually within one working day. You do not need to contact your old network separately to cancel.
What is the difference between a SIM-only and a pay-as-you-go deal?
A SIM-only contract gives you a set monthly allowance of calls, texts and data for a fixed monthly fee, typically on a 1-month or 12-month rolling basis. Pay-as-you-go means you pay only for what you use, with no monthly commitment. SIM-only is nearly always cheaper for regular users; pay-as-you-go suits people who rarely use their phone.
Is it worth getting phone insurance through my network?
Network insurance policies typically cost £10 to £15 per month and cover loss, theft and accidental damage. Over a 24-month contract that adds £240 to £360 to your total cost. Compare this against standalone phone insurance providers such as Gadget Cover or your home contents insurance, which may cover your phone at no extra cost.
How long should my mobile contract be?
A 12-month SIM-only contract gives you flexibility to switch if better deals emerge. A 24-month handset contract locks you in but often brings a lower effective monthly cost on the handset element. Avoid 36-month contracts unless the saving is substantial; technology moves quickly and you may want to upgrade before the term ends.
What happens if I exceed my data allowance?
Most UK networks automatically add a data bolt-on if you exceed your allowance, which can cost £3 to £10 for an extra gigabyte. Some networks, including giffgaff and Smarty, simply slow your speed rather than charging extra. Check your network's overage policy before signing, and set a data usage alert in your phone settings.