Giffgaff (stylized giffgaff) is a mobile telephone network running as a Mobile Virtual Network Operator (MVNO) using the United Kingdom O2 network.n 17 October 2012 Giffgaff added data only goodybags, called gigabags, to their lineup of products. In March 2014 Giffgaff announced that it would add a line of 4G LTE goodybags available for purchase from April 2014.