Understanding SIM cardsClose Article
SIM cards come in three sizes:
- Standard SIM - used in most older mobiles
- Micro SIM - used in the iPhone 4 and devices from that period
- Nano SIM - used in newer devices
New SIM only customers / Replacement SIMs / Pay as you go SIMS
We'll send you a Tri-SIM which contains each different SIM size, so you don't have to worry about ordering the correct SIM type. You'll need to pop out the right sized SIM from the plastic card to fit in your device. On the reverse of your card you'll see your mobile number and SIM serial number.
If you pop out the wrong sized SIM then you'll need to get a replacement. You can pick one up at your nearest store or order one online.
If you're an existing pay monthly customer you can also pick up a SIM in store or online - don't worry that it's pay as you go because we'll help you switch it over. Once your new SIM arrives you can perform a SIM swap if you still have access to your original SIM and if you don't have the original SIM, call 0345 301 4455 or 4455 from a Tesco Mobile device.
Your SIM will already be in your phone so you don't need to worry about anything.
Upgrading your phone
Your new device will come with a new SIM card, but you only need to use it if your current SIM doesn't fit into your new device.
If you need to use your new SIM, here's everything you need to switch over.
Problems with your SIM?
If you're having trouble inserting a SIM card into your device, our device guides provide step-by-step instruction for every device to help.