Everything you need to know about mobile unlocking. Find out which networks lock, how to unlock your handset and where to buy a new unlocked smartphone.

LockedIn the UK, many mobile networks will lock your smartphone to their network so you won’t be able to use the handset on another network. The process of removing these restrictions is known as ‘mobile unlocking’.

In this article, we’ll discuss the benefits of unlocking of your smartphone: how it will allow you to access cheaper tariffs both in the UK and abroad and how it allows you to make better second-hand usage of the smartphone. We’ll also look at the handset locking policies of different UK networks, how to unlock an existing smartphone and where to buy a new unlocked handset.

Benefits of Unlocking

There are three key benefits of having an unlocked smartphone:

  1. You can access cheaper deals when at home in the UK. Many people save about £20/month (£240 per year) by switching over to a SIM-only deal.
  2. You can change to a different SIM card when travelling abroad – this could save you substantial amounts of money compared to roaming on your normal UK tariff.
  3. An unlocked smartphone will retain its value much better. Whether you’re giving your old handset to friends & family or whether you’re selling the phone on eBay, it will be a much more attractive second-hand device.

It’s perfectly legal to unlock your smartphone and almost all UK networks provide a way for you to do it. Unlocking will not affect the warranty of your device (assuming that the unlock is done officially through your mobile phone network).

Access Cheaper Tariffs In The UK

For many people, the primary reason for unlocking their smartphone is having the ability to be able to use it with a cheap SIM-only deal.

A SIM-only deal is an airtime-only contract where you’ll get a generous allowance of minutes, texts and internet for a low monthly price (they’re often about £20/month cheaper compared to normal traditional contracts). You can keep your current phone number when changing to these deals but you might need to unlock your smartphone before you’re able to change over.

SIM card
With an unlocked smartphone, you can switch to a SIM only deal where you’re able to benefit from much cheaper rates.

Our recommended SIM only deals currently include:

BT MobileUnlimitedUnlimited4GB£10.00
inc. £5 discount
ASDA Mobile600Unlimited2GB£10.00
Tesco Mobile1,5005,0004GB£11.00

* A £5/month discount is available on BT Mobile for customers who live in a BT Broadband household.

Typically, SIM-only contracts have a 12 month commitment. For greater flexibility, you can instead choose a one-month rolling contract. For a complete overview of all the available options, see our guide to the UK’s best value SIM-only deals.

Save Money When Travelling Abroad

Going Abroad
You can also save money when travelling abroad.

If you’re travelling abroad and using your normal UK SIM card, you can quickly run up a large bill for international roaming if you’re using your normal UK SIM card.

With a specialist SIM card or with a locally-purchased SIM card from the country you’re visiting, you can often save a huge amount of money on roaming. Before you’re able to use another network when abroad, you’ll need to first unlock your smartphone (this is the case even if you’re using another country’s branch of the same network group e.g. Vodafone Spain or Three Italy).

Travelling to Spain, France, Italy, the USA or one of 14 other countries?

If you’re travelling to one of 18 selected countries, the best way of using your smartphone abroad is by taking advantage of Three’s Feel At Home offer.

Feel at Home Flags
Feel At Home is available in 18 countries including Spain, France, Italy, the USA, Australia and Ireland.

With Feel At Home, there’s no extra charge for using your smartphone abroad. Better still, you can benefit from the offer regardless of which network you normally use in the UK. Just order one of Three’s All-in-One Pay As You Go SIM cards and you’ll be able to benefit from the offer in any unlocked smartphone. A £10 top-up will give you 1GB of data, 100 minutes and 3000 texts (all available to be used when abroad). Meanwhile, a £20 top-up will give you 12GB of data, 300 minutes and 3000 texts (again, all available to be used when abroad).

Network Minutes Texts Internet Monthly
Three 100 3,000 1GB £10.00
Three 300 3,000 12GB £20.00

Three’s All in One Pay As You Go bundles can be used in conjunction with their Feel At Home offer. The inclusive minutes, texts and internet can be used abroad in any Feel At Home country. The £20 bundle has a fair usage policy of 12GB/month when in a Feel At Home country.

Countries included in Feel At Home: Australia, Austria, Denmark, Finland, France, Hong Kong, Indonesia, Israel, Italy, Macau, New Zealand, Norway, Republic of Ireland, Spain, Sri Lanka, Sweden, Switzerland and the United States of America.

Order Three Pay As You Go SIM Card (with £10 bundle) →

Second-Hand Usage & Resale Value

An unlocked smartphone will give you additional benefits in terms of easier second-hand usage and a higher handset resale value.

If you’re passing your old smartphone on to friends or family members, they’ll be able to use an unlocked smartphone on their network of choice (this includes on any of the best value SIM-only deals).

For second-hand sales (e.g. on eBay and Gumtree), an unlocked smartphone will often sell for a higher price. The potential audience of buyers will also be much higher (as customers of any mobile network can buy your old handset).

Which Mobile Networks Lock Their Smartphones?

  • EE
  • giffgaff
  • O2
  • Tesco Mobile
  • Three
  • Virgin Mobile
  • Vodafone

In the UK, most mobile networks lock their handsets before they provide them to you so you can only use it on their network. The main exceptions are giffgaff and Three who provide fully unlocked smartphones to all customers on their network. Virgin Mobile also normally provides an unlocked smartphone to customers on Pay Monthly.

The following table gives a quick summary of which mobile networks currently lock their smartphones:

Mobile Network Pay Monthly Handsets Pay As You Go Handsets
EE Will typically be locked Will typically be locked
giffgaff Will be provided unlocked Will be provided unlocked
O2 Will typically be locked Will typically be locked
Tesco Mobile Will typically be locked Will typically be locked
Three Will be provided unlocked Will be provided unlocked
Virgin Mobile Will be provided unlocked Will typically be locked
Vodafone Will typically be locked Will typically be locked

Mobile networks often choose to lock their smartphones as they may subsidise the upfront cost of the handset. By offering a new phone as a loss-leader, they’re able to attract new customers to their network. The network-locking mechanism is a way to stop you from taking a subsidised device and from immediately using it on another network (this would cause a loss to the mobile network that subsidised your handset).

On request, almost all UK mobile networks will now unlock your smartphone. This will sometimes be done for free but other times, you’ll need to pay a small fee for the unlocking (up to £19.99). You may also need to have been a customer on the mobile network for a certain amount of time before you qualify for this service.

Find Out Whether Your Phone Is Locked

SmartphonesThe table above should give you a good indication about whether your smartphone is likely to be locked to a network. If you’re still not sure about whether your smartphone is unlocked, the best way to check is by ordering a free Pay As You Go SIM card. The SIM card should come from another mobile network (though there are a couple of caveats*, see below for details).

When your new SIM card arrives, insert it into your smartphone. If the SIM card is accepted and you can see the name of the network being shown on the screen, then your smartphone is unlocked and there’s nothing further you’ll need to do. If you see an error message such as “SIM Not Valid” or “Invalid SIM” then your smartphone is currently locked and you’ll need to unlock it.

* Caveats: A giffgaff SIM card may work in your iPhone even if it’s locked to O2. A SIM card from EE will also work in iPhones that are locked to T-Mobile. You should bear this in mind when testing the phone with a SIM card from another network (ideally you should test the handset on a network that uses a different coverage provider).

SIM Not Valid: The SIM card that you currently have installed in this iPhone is from a carrier that is not supported under the activation policy that is currently assigned by the activation server. This is not a hardware issue with the iPhone. Please insert another SIM card from a supported carrier or request that this iPhone be unlocked by your carrier.
If you see a message saying “SIM Not Valid” or “Invalid SIM” then your smartphone is locked to a network.

When ordering a SIM card for your handset, be sure to order a SIM card of the right size.

How To Unlock Your Smartphone

UnlockThere are four simple steps to unlocking your smartphone:

  1. Find out whether your smartphone is already unlocked. If you’re still not sure, a good way to check is to order a free Pay As You Go SIM card from another network.
  2. Obtain the IMEI number for your smartphone. If you need to unlock your smartphone, the next step is to obtain your 15-digit IMEI number. This is a unique identifier for your smartphone and you can find it by entering *#06# on your telephone keypad (star hash zero six hash).
  3. Ask your mobile network to unlock the smartphone. Depending on your network and tariff, this could either be free or it could cost you up to £19.99. For more information, see our guides on unlocking an iPhone and unlocking a Samsung Galaxy.
  4. When the unlock has been processed, enjoy using your new mobile network or SIM card. It can take anything from a couple of hours to 10 working days for your unlock to be processed. Once this is done, you can enjoy cheaper rates at home and cheaper rates when abroad.

For more information, you can follow our step-by-step guides on unlocking an iPhone and unlocking a Samsung Galaxy smartphone. If you have a different Android smartphone, you can still follow most of the instructions in our Samsung Galaxy article (the menus will look a bit different on your phone but the instructions for unlocking will be exactly the same).

Where To Buy A New Unlocked Smartphone

Apple iPhone


If you’re looking to buy a new unlocked iPhone, the best place to buy it is generally John Lewis. They provide permanently unlocked at the same price as Apple with an added two-year guarantee at no extra charge. Unshackled is another online retailer that sells permanently unlocked iPhones, with the option for you to spread the cost out over 24 months.

You can also buy a new unlocked iPhone from giffgaff or Three on Pay As You Go. Both giffgaff and Three provide the iPhone permanently unlocked, so you’re able to use it on any mobile network. There’s no obligation to actually use the iPhone on giffgaff or on Three, but you’ll normally need to get a SIM card from them at the same time as when you order (this may have a £10 minimum top-up requirement).

The following table compares how much you’d pay for an unlocked iPhone at the Apple Store, giffgaff, Three, John Lewis and Unshackled:

Handset Apple Store giffgaff* Three* John Lewis Unshackled
iPhone 7 £599.00 £599.00 £599.00 £599.00
iPhone 7 Plus £719.00 £719.00 £719.00 £719.00
iPhone SE £379.00 £329.00 £379.99 £379.00 £359.00
iPhone 6s £499.00 £499.00 £499.99 £499.00 £499.00
iPhone 6s Plus £599.00 £599.00 £599.99 £579.00 £599.00
iPhone 5s £199.00 £249.99

iPhone prices were correct as of the 9th December 2016. * On giffgaff and Three, you can get a permanently-unlocked iPhone on Pay As You Go. You’ll need to order a Pay As You Go SIM card at the same time, with a minimum top-up of £10 on the SIM card. There is no obligation to actually use the SIM card: you can easily use the handset on another mobile network.

In general, we wouldn’t recommend buying a SIM-free iPhone from any other retailer. Though you may be able to save a bit of money, their SIM-free iPhones will automatically lock to the first network used. You’ll then subsequently need to go through the process of unlocking the iPhone from your first mobile network (this can be greatly complicated by the fact you bought your iPhone from another retailer). SIM-free iPhones from a third-party retailer will also be restricted to working only on UK mobile networks.

All Other Smartphones

Android Smartphones
For all other smartphones, there’s a wide variety of online retailers where you’re able to buy an unlocked smartphone.

If you’d like to buy an unlocked smartphone that isn’t an iPhone, there’s a wide choice of retailers you’re able to choose from.

If you’re happy to get the phone on a Pay Monthly contract, try the Carphone Warehouse or Mobiles.co.uk. Both of them will provide you with an unlocked handset on a 24-month contract (the contract will often be the same price or slightly cheaper than getting it directly from your mobile network).

On Pay As You Go, you can get a handset from either giffgaff or Three (both giffgaff and Three provide their handsets unlocked so you’ll be able to use them on the mobile network of your choice).

Finally, for a SIM-free smartphone (without a contract or SIM card), you can go to one of the following online retailers:

Often, you’ll also be able to buy a SIM-free smartphone directly from the manufacturer (e.g. from the HTC, Microsoft, Motorola, Samsung or Sony official websites).

More Information

For more information about unlocking your smartphone, please see our step-by-step guides to unlocking an iPhone and unlocking a Samsung Galaxy. Once you have an unlocked smartphone, you may find it of interest to see our guide on the best value SIM-only deals.

Your Comments 85 so far

We'd love to hear your thoughts and any questions you may have. So far, we've received 85 comments from readers. You can add your own comment here.

  • Hi
    great informative site!I am travelling to South Africa shortly and want to be able to surf the net and email from a place with no wifi. What is the best option for me? I have a Sony smart phone that I bought from O2, then took out a sim only contract with Bt that involved O2 unlocking the phone. I assume it is unlocked but have taken your advice and ordered a free sim from Asda to try. Should I buy a sim card in South Africa (or get my relative to get it) and buy data……. will it work ok?

    • Hi Lorraine,
      Thanks for your comment. Yes, your best bet would probably be getting a local SIM card while you’re out there in South Africa (as most UK networks will have extortionate roaming charges there). As you say, it’s definitely worthwhile making sure your handset is unlocked before you go, and ordering a SIM card from another network like ASDA Mobile is a great way to do this!

  • Hello. I’m having a torrid time getting a tesco phone unlocked. It’s a MOTO G and the contract is up so I’ve moved to talk talk on a sim only deal. Tesco have given me a code but it doesn’t work. They say they’ll send me another one in twenty days. I have bought one off eBay and it’s exactly the same as the one I received from tesco. I have powered off my phone, inserted the talk talk SIM card, and turned it on again. It says “sim network unlock pin” but when I input the code it says unsuccessful. I have spoken to talk talk and they say everything is fine at their end. I have read that tesco phones are double locked. Is that true? If so what does that mean? Is there anything I can do about it?

    With many thanks PAUL.

    • Hi Paul,
      Thanks for your comment. I believe ‘double locking’ means the handset is specifically locked to Tesco Mobile (as opposed to some MVNOs that only lock the handset to their coverage provider e.g. in this case, you’d be able to use the handset on O2 and other O2 MVNOs).
      Either way, this shouldn’t affect the unlocking process for your smartphone. Once you’ve received the code from Tesco Mobile and got it to work on your phone, it will then be unlocked for use on any network. Sorry I can’t help any further – but the onus is now on Tesco Mobile to provide you with an unlock code that works.

  • hello i just bought an iphone 7 from carphonewarehouse and when i took it to morocco i couldn’t activate the card as my phone comes with is region lock even its a pay as you go sim free phone.
    if i activate my phone with 3 so it will be locked to three, and when in case i contact three to remove the lock! can this phone accept a foreign card.
    thanks for your time

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