If you're leaving giffgaff and moving to another network, you'll need to request a PAC (Porting Authorisation Code) from us in order to give it to your new provider.
Once issued, the PAC code is valid for 30 days (after which it expires). When you take your number from giffgaff you'll permanently lose any remaining giffgaff credit, goodybags and Payback points you've accumulated.
If you wish to bring an existing UK mobile number to giffgaff, you need to ask your current service provider for a PAC (Porting Authorisation Code). This article explains how to do this.
Another way to get the code is by using your phone. Just:
Text 'PAC' to 65075 or
Dial 43431 and follow the instructions
You'll receive an SMS with the PAC code and its expiry data plus a voice confirmation of your PAC if you've chosen to call. The information will be also be displayed on your My giffgaff dashboard under your mobile number.
If you've any questions about transferring your number, Ofcom has some handy links and tips here.