on 03-05-2013 05:08
As in previous answers on this years old thread, its printed on the back, the sim carrier and the envelope it came in.
on 20-10-2015 17:26
Unless you have the original packaging you need to call customer service. They know the sim number.
on 20-10-2015 17:55
Lumia 950 Dual (O2 & Sfr) and Z3 Tablet (Three UK)