Transferring balance from one o2 sim to another

[Anonymous]

I have just received a new sim from o2 for an unlocked windows phone. I already have an o2 pay as you go phone with approx £25 credit, how do I transfer this balance to my new device

[Bambino]

If your old sim is the same size as the new one, just put the old sim in the new phone. 

[jonsie · Accepted solution]

O2 will transfer the credit for you but will reclaim the original number so it can't be used.  Call them,  not  live chat. 

[Cleoriff]

Yes when I transferred to contract from PAYG it needed a call to CS to transfer my balance to my new contract account. http://www.o2.co.uk/contactus

[Bambino]

Maybe it's just me, but I read the OP's post as them just wanting to use their Pay & Go sim in a new phone and were sent a new sim which wouldn't be needed if the sims are the same size? They aren't looking to change account type.

[MI5]

Just do a sim swap http://swapmysim.o2.co.uk/