Guide to Switching Mobile SIMs

Switching mobile SIM cards has become easier than ever before. Whether you’re looking to change your mobile network provider, upgrade your plan, or simply want to switch to a new phone, this guide will walk you through the process step by step. Read on to discover how to make a seamless transition with your mobile SIM in the UK.

  1. Check Your Current Contract: Before making any changes, ensure your current contract is up for renewal or free from obligations.
  2. Choose Your New Mobile Network: Research and select a mobile network provider that best suits your needs in terms of coverage, plans, and pricing.
  3. Order a New SIM Card: Place an order for a SIM card from your chosen provider, either online or by visiting a local store.
  4. Back Up Your Data: Ensure all your contacts, photos, and important data are backed up to avoid losing anything during the switch.
  5. Receive and Activate Your New SIM: Once your new SIM arrives, follow the activation instructions provided by your new network provider.
  6. Test Your New SIM: Insert your new SIM card into your phone and ensure everything is working as expected.
  7. Request a PAC Code: If you want to keep your existing phone number, contact your current provider and request a Porting Authorisation Code (PAC).
  8. Provide PAC Code to New Provider: Share the PAC code with your new provider to initiate the number transfer process.
  9. Wait for the Switch: Your new SIM will be activated, and your old one deactivated. This usually takes a few hours to complete.
  10. Test Your New SIM again after your old number has transferred: Insert your new SIM card into your phone and ensure everything is working as expected.

If you did not request a PAC code, you should inform contacts of your new number.

Here are coverage checkers for different networks

Here is more information about getting a PAC code

Here is more information about backing up data


Switching mobile SIM cards in the UK is a straightforward process that can be completed in a few easy steps. By following this guide, you can smoothly transition to your new mobile network provider while keeping your phone number and important data intact. Enjoy your improved mobile experience!