Swap your SIM

To swap your SIM, you’ll need to sign in to My O2. If you're making the request from a laptop, desktop or tablet, make sure you have your phone with you, as we’ll send a security text before we do the swap.

If you're an O2 Business customer, please sign in to My O2 Business to swap your SIM.

Before swapping, you’ll need to check that your SIM is the correct type. Our Pay Monthly SIMs are set up differently to Pay As You Go ones and they’re not interchangeable, so you’ll only be able to swap on to a SIM that matches your account type.

Help with your SIM

Need help with your SIM? We've got you covered. You'll find all the information you need in the sections below.

If you're popping into one of our stores to swap your SIM, remember to bring your passport or driving licence with you, as ID. 

Our SIM types

Plastic SIMs

Plastic SIMs come in three different sizes - standard, micro and nano. The SIM pack has perforated edges, so you can just pop out the SIM that’s the right size for your device.

If you're not sure which size SIM you need, have a look at the instructions that came with your device.

Don't try to cut your old SIM down to size, as it could break or get stuck in your device. If you need to use your nano or micro SIM as a standard SIM in an older device, you can get a free adaptor from one of our stores.


Some devices allow you to use an eSIM. Check out our eSIM help page to find out more.

Replacing your SIM

You can get a replacement SIM by logging into My O2  

Activating your SIM

New Pay Monthly customers

If you’re using a plastic SIM, your SIM is ready to use straight away. Just pop it in your device and you're good to go. If you’re using an eSIM, you’ll just need to download the eSIM profile to your device, using the QR code in your eSIM pack.

New Pay As You Go customers

If you have a Pay As You Go plastic SIM, you’ll need to put it in your device and then top up to activate it.

Existing Pay Monthly customers 

  1. If you don’t have your current SIM, or it’s no longer working, either put the new plastic SIM into your device or download the new eSIM profile to your device. If your device connects to our network, you can start using your new SIM straightaway. 
  2. If your device doesn’t connect to our network, call us from a landline and we’ll help. You’ll need to confirm your identity, so we can protect against fraud. 
  3. If you have your current SIM and it’s still working, don’t remove it from your device straight away – we’ll need it to send you a security text. You’ll also need the 13-digit SIM Serial Number (SSN) for your new SIM, which begins 00. You’ll find this printed on the back of your plastic SIM card or on your eSIM pack.
  4. To move your mobile number across to your new SIM, sign in to My O2.
    If you're an O2 Business customer, please sign in to My O2 Business to swap your SIM.


SIM swaps can take up to 24 hours to complete. Once you lose signal with your original SIM, turn your device off. Turn it back on and, if you’re using a plastic SIM, pop it in your device. Wait till you see our network appearing on your device.

Unblocking your SIM and PUK code

If you've blocked your SIM from entering your PIN too many times, you'll need to request your PUK (Personal Unblocking Key) code. Fill out the form to unblock your phone.

Lost, stolen or damaged SIMs

If your SIM has been lost or stolen, you'll need to contact us by phone to block your SIM and order a replacement.

Your replacement SIM will come activated and set up with your existing number, so all you need to do is insert it into your device.

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