How to Save Money on Your Mobile Phone Contract Using Comparison Sites
Published 21st of February 2012·Updated 5 April 2026
Reviewed by: Reviewed for accuracy April 2026
Comparing mobile phone contracts before signing up can save you a significant amount over a typical 24-month deal. Networks including EE, O2, Vodafone, Three, and giffgaff each price the same handset differently, and using a comparison tool is the quickest way to find the cheapest contract for your exact usage needs.
Short Summary
The same handset can cost hundreds of pounds more over a 24-month contract depending on which network you choose. EE, O2, Vodafone, Three, Sky Mobile, and Virgin Mobile all offer different tariffs for the same phone.
Mobile comparison sites such as Uswitch, MoneySuperMarket, and comparethemarket allow you to filter by minutes, data allowance, and monthly cost, so you only see contracts that match your actual usage.
SIM-only deals on a rolling monthly basis are significantly cheaper than handset contracts for people who do not need a new phone. A SIM-only 5G plan with unlimited data can cost as little as £8 to £15 per month from networks such as Three, SMARTY, or Lebara.
Buying a handset outright and pairing it with a cheap SIM-only deal is often cheaper overall than taking a contract, particularly for mid-range phones. Calculate the total cost over 24 months before deciding.
How do mobile phone comparison sites work?
Mobile comparison sites aggregate deals from multiple networks and retailers in one place. You enter your requirements, such as minimum data allowance, preferred network, and budget, and the site returns a ranked list of matching contracts.
Sites such as Uswitch and MoneySuperMarket include deals from networks such as EE, O2, Vodafone, Three, and Sky Mobile, as well as online retailers such as Mobiles.co.uk and e2save. Some exclusive tariffs are only available through specific retailers, so comparing across sites gives you a wider picture than visiting network websites individually.
What type of mobile deal is cheapest: contract, SIM-only, or PAYG?
The cheapest option depends on whether you need a new handset and how much data you use.
| Deal type | Typical monthly cost | Best for |
|---|---|---|
| Handset contract (24 months) | £25-£70/month | New phone + high data needs |
| SIM-only (12-month) | £8-£25/month | Keeping existing phone |
| SIM-only (monthly rolling) | £5-£20/month | Flexibility, lower data use |
| Pay as you go | £5-£15/top-up | Very light users |
A handset contract bundles the cost of the phone into your monthly payments. This is convenient but you often pay more for the phone than if you bought it outright. A useful test: add up the total cost of a handset contract over 24 months, then compare that to buying the phone outright and pairing it with a 24-month SIM-only deal. The SIM-only route is frequently cheaper by £100 to £300.
How do I know how much data I actually need?
Most smartphones show your data usage in their settings. On iPhone, go to Settings, then Mobile Data. On Android, go to Settings, then Network, then Data Usage.
As a rough guide:
- 1GB to 3GB per month: light users who mainly use Wi-Fi
- 5GB to 15GB per month: moderate use including video streaming on the go
- 20GB or more per month: heavy streaming, remote working, or frequent travel
Many networks now offer unlimited data plans at competitive prices. Three, SMARTY, and giffgaff are consistently among the cheapest for unlimited data. If you regularly use mobile data for video calls or streaming, unlimited data removes the risk of overage charges and is often better value than a capped mid-range plan.
When is the best time to switch mobile contracts?
The best time to switch is when your current contract ends. Staying on after your minimum term means you continue paying a monthly rate that includes an element for the handset you have already paid off. Your network is legally required to notify you between 10 and 40 days before your contract ends, under Ofcom rules, which is your signal to start comparing.
If you want to keep your existing phone number, request a PAC (Porting Authorisation Code) from your current network. Your network must provide this by text within two seconds of request. Give the PAC to your new network and your number transfers within one working day.
Are there any hidden costs to watch for on mobile contracts?
Yes. Common additional costs include:
- Roaming charges: EE, O2, and Vodafone reintroduced EU roaming charges for some plans. Check whether your contract includes free EU roaming before travelling.
- Out-of-bundle charges: calls or data beyond your monthly allowance can be expensive. Check the per-minute and per-MB rate in the contract terms.
- Upfront handset costs: some "£0 upfront" deals have higher monthly costs that more than compensate over the contract term.
- Mid-contract price rises: most major networks apply annual price rises linked to the Consumer Price Index (CPI) plus a fixed percentage. Ofcom requires networks to disclose this clearly, but check the terms before signing.
Frequently Asked Questions
Which network has the best coverage in the UK?
EE has the widest 4G coverage in the UK, reaching over 99 per cent of the population. Vodafone and O2 also have strong national coverage. Three has the most extensive 5G network in terms of geographic reach. Use the Ofcom coverage checker at checker.ofcom.org.uk to see which networks cover your home and workplace address.
Can I keep my phone number when switching networks?
Yes. Request a PAC (Porting Authorisation Code) from your current network by texting "PAC" to 65075. The code arrives by text within seconds and is valid for 30 days. Give it to your new network when you sign up.
Is a SIM-only deal worth it if my phone is old?
SIM-only is worth it as long as your phone still works reliably and receives security updates. Most Android handsets receive updates for three to five years; iPhones typically receive them for six years or more. If your phone is out of security support, consider a budget handset rather than a premium one, and pair it with a cheap SIM-only plan.
What does unlimited data actually mean on a mobile contract?
Unlimited data means there is no cap on your data allowance, but some unlimited plans include fair use restrictions that slow your connection (throttling) after you reach a certain threshold, typically 100GB to 200GB in a month. Check the fair use policy in the contract terms if you are a very heavy user.
How much can I save by switching to a cheaper mobile deal?
The saving varies, but switching from a premium handset contract to a SIM-only deal on a cheaper network can save £20 to £40 per month, or £480 to £960 over two years. Even switching between handset contracts on different networks for the same phone can save £5 to £15 per month.