Hi giffgaff do not distribute Nano SIMs directly Go here to order one
you can then do a Sim SWAP already on giffgaff: do this, you will be able to transfer your giffgaff account (including your phone number, credit and any existing bundles) from your old sim to your new sim. This is known as a 'SIM Swap' - for more details, please see here: http://community.giffgaff.com/t5/Learn-giffgaff-Top-Tips/How-to-use-SIM-Swap/td-p/6885194
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