If you’re thinking about changing network provider, you might be concerned about using a different SIM in your phone. That’s because some phones are locked to a particular provider, preventing the use of a SIM card from a different network. If your phone is locked and you try to use a different SIM, you won’t be able to use your minutes, texts or data. Here, we show you how to unlock your phone and use any SIM.

If you're here looking for how to unlock your phone because you've forgotten your password, pin or passcode, click here.

Is it legal to unlock your phone?

If you’ve finished paying for your contract, it’s completely legal to unlock your phone. The same goes for any phone you purchased outright. However, if you’re still in the process of paying off your initial contract you technically do not own the phone yet, and therefore it’s a bit of a grey area. We’d recommend checking terms with your carrier before you proceed.

If you think your phone might already be unlocked (many are), you can find out how to check in our guide: Is my phone unlocked?

How to unlock your phone

Unlocking a phone can be surprisingly easy once you know how.

1. First, you’ll need to contact your provider and request an unlock. This must be the original network, not the network of the new SIM you’re trying to use.

2. Once you’ve had confirmation that your phone has been unlocked by your provider, you can power down the phone, put your new SIM card into the SIM card slot, and turn the phone back on.

3. Now, try making a call to find out whether or not the unlock has been successful. If you’re able to connect a phone call over the new network, the unlock has worked. If not, get back in touch with your network provider for further assistance.

If you don’t have the original SIM card, you may need to reset the phone before it can be unlocked. Find out how: How to factory reset Android.

Contact your network provider

Taking a closer look at step one, we’ve listed each of the popular network providers in the UK to help you find out how to go about unlocking your phone. Find your carrier from the list below and follow the instructions provided.

EE

EE states that any iPhone or iPad sold directly by EE on or after 1 September will be unlocked automatically once it reaches 18 months old. Other phones may be slightly different, though.

To unlock your EE phone, you must be the account holder for the device and number, have had the device for at least six months, have paid your bill up-to-date and have not reported the device as lost or stolen.

If you have an EE pay monthly device, you’ll be able to get your phone unlocked for free if you’ve finished your contract. If you haven’t, it will cost £8.99 to unlock it. The same goes for a pay as you go device (free if bought direct with EE by the requester, or £8.99 if not).

Any second hand device locked to EE that you purchased via eBay, Gumtree etc will cost £8.99 to unlock, as will any EE small business devices.

EE aims to unlock your phone within 72 hours, but it can take up to ten days in some cases.

You can find out more about unlocking your EE phone and contact EE directly by clicking here.

Giffgaff

Giffgaff is a bit unusual in that it offers an ‘Unlockapedia’ that you can use to search for your phone make and model to find out how to go about unlocking it. You’ll find the Giffgaff unlockapedia here.

O2

O2 will unlock your phone at any time, for free if you are on a Pay Monthly tarrif (there are some exceptions if you have a new, flagship phones like the iPhone X. For those you’ll need to wait until you’ve paid off your phone in full).

If you’re a pay as you go customer, it’ll cost you £15 to unlock your phone if it’s been 12 months or more. If it’s been less than 12 months O2 won’t be able to unlock your phone for you.

You can find out more about unlocking your phone on O2 here.

Sky Mobile

Phones purchased via Sky should already be unlocked, so you won’t need to get in touch with the company to unlock your phone. Instead, try your new SIM and it should work. If you’re using an iPhone, you may need to go into Settings > Mobile Data > Mobile Data Options > Mobile Data Network > Reset Settings.

Tesco Mobile

If you’ve got a pay as you go phone with Tesco Mobile, it will be free to unlock 12 months after it was activated. To unlock it before that it’ll cost you £10.

Pay monthly devices are also free to unlock with Tesco Mobile, unless it’s a brand new, flagship phone like the iPhone X or Samsung Galaxy S9.

It can take up to 20 days to unlock a phone on Tesco Mobile, but the company says it normally takes seven.

To unlock your phone you’ll need to know your IMEI number (find it by dialing *#06#) and then call Tesco Mobile on 03453014455.

Three

Three has an online unlocking form available, but if you purchased your phone from Three after 1 January 2014 your device will already be unlocked.

Virgin Mobile

Most Virgin Mobile phones will already be unlocked, so you should have no trouble here. Just try the new SIM card and it should work without requiring any further action.

Vodafone

You’ll be able to use Vodafone’s online unlock request form here. It may take up to 10 working days to recieve an unlock code from the company. You’ll need to be up to date with your bills, too.

Using a third-party unlocking service

We would always recommend checking with your network provider before you resort to a third-party unlocking service, but sometimes it can be much quicker and easier.

It’s important to watch out for third-party unlocking services that sting customers with extra bills at the end of the process, so be sure to read the small print before you hand over your money.

We’ve tried and tested Doctor SIM, which promises a refund if the unlock is unsuccessful and didn’t surprise us with any hidden fees. It could be an option if you’ve tried the methods listed above.

We wouldn’t recommend paying anything more than £25 to have your phone unlocked. If someone is trying to charge you more than that, they are trying their luck.

For more details instructions about how to unlock an iPhone, visit our sister site Macworld's tutorial here.