How to use or activate your SIM

New connection

If you've just purchased a new connection and received your new SIM card, it should already be activated. Simply pop it into your handset and you're good to go.

Replacement SIM

If you've manually requested a replacement SIM card due to your old SIM being lost, stolen or damaged, you will need to activate it before you can use it.

Activate your SIM here


If you've received a new SIM after upgrading, you can ignore this and continue to use your current SIM. Your new plan will be active on your current SIM card within 24 hours.

SIM card sizes explained

When you get a SIM card from us it actually contains all three sizes. You simply choose the size you need, snap it out from the perforated edges, and insert it into the SIM card tray of your phone. Make sure you're certain of the SIM card size before you do this. Check the handset manual if you're not sure.

Standard SIM

Also known as 'The Big One'

Micro SIM

Also known as 'The medium one'

Nano SIM

Also known as 'The Tiny One'

What's your SIM card number?

Your SIM card number is the 19-digit number printed on the SIM card holder, under the barcode.

If you don't have the card holder any more, don't worry - the number's also printed on the back of the SIM card itself. It's an 11-digit number, and you just need to add '89442001' to the start of it if you need to input it somewhere.

Replacing your SIM

It's been lost or stolen

Let us know as soon as possible, so we can block it and send you a new SIM.

Please visit our Lost or Stolen page for instructions on how to do this, and what steps to take next.

It doesn't fit my phone

You can buy a SIM adapter from Currys.

Or you can also get a replacement SIM card for £5.00 at any Currys store.

SIM card not working?

If you receive a new SIM card and it doesn't seem to be working, here are two important things for you to try out and check.

1. Do you have coverage in your area?

Use our coverage checker to find out what the coverage is like in your local area.

Please note: the coverage checker is a computer-generated prediction. We can't guarantee how strong your indoor signal will be, as there are several factors that might affect it. Example: coverage in some rooms in your house may be better than other areas, or your outdoor coverage may be better than indoors.

For more information, check out our Coverage Support page.

2. Are you using an iD approved / compatible handset?

All handsets provided with an iD plan are compatible with our network. If you purchased a SIM only iD plan, and are using an iD compatible handset you bought elsewhere, that's fine.

Click here to view our list of 'iD Approved / Compatible Handsets'. If your device isn't on the list, your ability to use iD services may be affected.

Tried the above and it's still not working?

If you're using an iD approved/compatible handset, and our coverage checker shows good indoor and outdoor coverage, follow the troubleshooting steps below if your SIM card doesn't appear to be working.

  • Put your phone into flight mode, leave it for 30 seconds, then disable flight mode.
  • Check that the SIM card is inserted correctly.
  • Restart your device.
  • Turn off your device, remove SIM, and clean it using a micro-fibre cloth. Then re-insert it and try again.
  • Try the SIM card in another 'iD compatible handset', and test the connection in a few locations to see if the SIM connects. If you don't experience any issues with the other handset, your original phone may be at fault.

If none of the above works, get in touch with us and we'll help you out.

SIM is locked and you need the PUK code?

If you enter the wrong PIN to unlock the screen too many times, you might block your SIM! If this happens, you'll be asked to enter a PUK code to unblock it.

Your PUK code is an 8-digit pin. Be careful, because if you enter it incorrectly 10 times, your SIM card will be blocked permanently.

Talk to our Live Chat agents to request your PUK code.