Porting your mobile number from T-Mobile to giffgaff

Leaving T-Mobile

How to switch from T-Mobile and transfer my number to giffgaff

T-Mobile customer services can be contacted by either dialing 150 from a T-Mobile SIM, or 0207 362 0200 from another phone, to request your "Port Authorisation Code" (PAC) at the same time that you give your notice of leaving TMobile.

If you wish to use the 'text-to-switch' service, simply SMS text PAC to 65075 free from your T-Mobile SIM to request a PAC code by text message and begin the porting process.

  • T-Mobile will provide your Porting Authorisation Code (PAC) either by SMS text message, via email, or over the phone if you contact them.
  • A PAC number is valid for 30 days. If you don't use it within thirty days it will expire and you will need to request a new one.
  • Your T-Mobile online account settings will remain active until your number has been ported over to the new network. After the transfer is complete, your account will be automatically closed.

While you wait for your Port Authorization Code from T-Mobile, get the best giffgaff offer for you. Many of these exclusive mobile phone deals are only available online, directly from the network providers listed here.

Got your PAC code from T-Mobile?

Provide your PAC code from T-Mobile to giffgaff online who will then be able to port your existing phone number from T-Mobile. They will tell you what day the transfer is due to take place (usually within 48 hours).

Important: Do NOT cancel your SIM only or mobile contract before switching, otherwise you may lose your existing phone number and be unable to port it over. Once you give your new network provider your PAC code, your old billing account will be closed automatically when your number is successfully ported over.

Note: Credit on Pre-Pay / PAYG (Pay-As-You-Go) accounts cannot be transferred over and so any remaining credit balance will be lost after the switch is complete. If you have any credit left, one good option is to donate it to a charity by SMS text message before porting your number.

Joining giffgaff

How to switch to giffgaff and keep my T-Mobile number?

First get your giffgaff package and activate your new SIM card.

Once you have done that, get the following information ready to follow the step-by-step instructions:

  • Your old T-Mobile mobile phone number you want to keep.
  • The Porting Authorisation Code (PAC) from your previous T-Mobile network.
  • The expiry date of the PAC number (valid for 30 days from the date of issue).
  • The temporary mobile number from your new giffgaff SIM card activation.
  • You may also need the new giffgaff SIM card serial number found on the back.

Make sure your giffgaff account and SIM have been activated. Then log in to your account and complete the transfer form to keep your old number. A Giff gaff customer support agent will then get back to you with your transfer date. Replies can be found in your giffgaff account message box.

Note: You may lose network service for a short period on the day of transfer. If this happens, turn your phone off and on occasionally, until you see the giffgaff signal on your mobile phone screen. This will indicate that the transfer is complete, and you can now use your existing phone number in your new mobile network provider.

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About giffgaff

giffgaff is a mobile telephone network running as a Mobile Virtual Network Operator (MVNO) using the United Kingdom O2 network. Owned by O2's owners Telefónica, giffgaff was launched on 25 November 2009.

About T-Mobile

T-Mobile UK is a mobile network operator in the United Kingdom, owned by Deutsche Telekom since 1999, and originally launched as One2One.

In 2009, Deutsche Telekom and Orange SA announced that the T-Mobile network was to be merged with Orange UK in a joint venture with EE Limited to form the UK's largest mobile network.