Here's how to unlock your phone on Vodafone, Three, EE and O2, and how to get an unlocked phone on contract.

We show you the way to unlock your phone for free, and reveal which networks let you buy an unlocked phone from the get go

Having a locked phone precludes you from using other networks, and therefore from reaping the benefits of the mobile phone market's best deals. We show you how to unlock your mobile phone (in many cases for free), preventing you from being bogged down in a long and expensive contracts. Whilst this dynamic doesn't work in mobile phone companies' favour, many of them, including mobile giants Vodaphone, Three, EE and O2, do let you unlock, with many instances being absolutely free!

There are, natrually, caveats; typically all networks impose a limit (or three) on the unlocking process – time after activation to unlock, cost of unlocking and how long it will take to carry out. We'll explain how to do it on all the UK's major networks. So you can finally do away with dubious-looking high street unlocking services - anything they'll do you can do yourself for a fraction of the cost, if not for free.

What you need to know before unlocking your phone:

* Your mobile phone number
* Your account number (is known/applicable)
* Phone manufacturer
* Phone model
* IMEI number (dial *#06# or look on back of battery or the phone's box)

Need a SIM only plan for your newly unlocked phone? Check out the best sim only deals

Buying an unlocked phone from a mobile network

Some mobile networks permit their customers to buy unlocked phones from the get go. GiffGaff is one such example, and has become a household name accordingly; it lets you buy a phone outright and then pay monthly for data, texts and minutes, or you can pay monthly for the phone in the form of a loan. Either way, you get your phone unlocked and you're not trapped any form of contract (aside from with a loan, which you must repay) and can switch provider at any time.

Three also now sells all of its phones unlocked, although if you get a phone on contract you're unlikely to want to swap your SIM out unless you have major problems with its service or want to sell your phone or give it to a family member on a different network. Virgin Mobile sells its contract phones unlocked, as well as most of its pay as you go handsets.

How to unlock a phone on EE

This also applies for Orange and T-Mobile. EE has reduced the cost of unlocking a phone on its network; pay as you go, SIM-only and contract customers can get their phone unlocked for £8.99. Unlocking is done via an online form available here.

How to unlock phone on O2

O2 Pay monthly customers can unlock their phone at any time during their contract for no charge and it will take up to 10 working days to process. They can do so using My O2 online, or via the main menu of the My O2 app. Once unlocking is successful, users will be sent a text alert. However, if you've got an iPhone 8 (Plus), iPhone X or Samsung Galaxy S8 (Plus), you'll have to wait until you've paid your Device Plan off in full in order to get it unlocked. Pay as you go customers will need to wait for 12 months after activation and pay £15 for the service. Again it will take up to ten working days. Business customers can do this for free on a phone-by-phone basis, although iPhone 8 (Plus), iPhone X and Samsung Galaxy S8 (Plus) devices are not able to be unlocked, according to O2's website, iPhone . Full details here. An unlock code request form is available online.

How to unlock a phone on Three

If you purchased a handset from Thee since December 2013 then it is already unlocked and you don't need to do anything. People with older handsets that want to unlock them can do so free of charge. Both pay as you go and pay monthly customers should fill in the online form, with unlocking taking up to seven working days.

How to unlock a phone on Vodafone

Unlocking your Vodafone device is free of charge if you're a personal customer, just fill in the online form to unlock your handset. Business customers might incur a charge for this service. Whilst the unlocking process can take up to 10 working days, but you should receive a confirmation email when your application is received, and another within 47 hours if they alerady have the code. 

How to unlock a phone on Tesco Mobile

You can unlock a Tesco Mobile phone at any time on both pay as you go and pay monthly. On pay as you go it will cost you £10 if the phone was activated less than 12 months ago and there's no charge after 12 months. With pay monthly plans it's free to unlock handsets. Often if they're new devices (i.e. they've just been launched), you might not be able to unlock them straight away (as above). You'll have to email or call Tesco Mobile to unlock your phone as there is no online form.

How to unlock a phone on Virgin Mobile

Virgin Mobile currently sells all its pay monthly handsets unlocked, but some sold before July 2012 may require unlocking. Virgin says the vast majority of its pay as you go phones come unlocked. Pay as you go and pay monthly customers can unlock their phone whenever they want for £15.32. The process should be completed within a few hours but could take up to five days if a code needs to be retrieved from the original manufacturer. You'll need to give Virgin Mobile a call as there's no online form.