Is Giffgaff sim cards in partnership with O2?

I have a iPhone and it's only open to O2 will the Giffgaff card be okay for my phone
Please share any info

Most partner "virtual" networks (Ikea, tesco, Asda etc) use their own network code
and will be locked out of a Vodafone/O2/T-mo/Orange etc locked phone
even if they are on the same network.

That said, O2 and GiffGaff do seem to be interchangeable - all reports seem to say so
O2 will work in GiffGaff locked phone
GiffGaff will work in O2 locked phone

only you putting one in your phone will show it
(also know that if you got your phone at Carphone warehouse or Phones4U not an O2 shop, it may well not be locked anyway - even if it had O2 branding)

They are not in partnership as such, but your O2 locked iPhone will work fine with a Giffgaff sim, as Giffgaff use O2's transmitters to run their network. I have been with Giffgaff since they started. Have a look at the link below, where you can ask any questions about the network.

http://giffgaff.com/support

If you wish to join Giffgaff, you can get a simcard at the link below. If you order from the link, I will receive 500 points towards my payback, and you will receive £5 extra credit when you first top up with £10 or more.

http://giffgaff.com/orders/affiliate/borobabe