If we exclude Carphonewarehouse, iPhones bought from the networks are already locked by serial number before you put your sim in.
Carphonewarehouse is hit or miss as I (other half actually) have an iPhone which is unlocked from them on contract..

Can I please piggyback on to the back of this thread?

I have an iPhone 5 on contract with Virgin which has a year still to run.

Due to my deteriorating eyesight I am considering buying a larger phone (iPhone 6?) sim free. I had assumed that I could simply move the sim from the iPhone 5 to my new phone and continue paying Virgin for the rest of my contract.

I had intended to give the unwanted iPhone 5 to my OH assuming that he could put his sim from his crappy cheap Samsung Young in it. However he is on a PAYG tariff with Vodaphone (since he very rarely uses it).

I am beginning to think I might not be able to do this .

There is no problem doing that.



As long as you get the iPhone unlocked by Virgin (if it is locked) then there is no problem your OH using it.

So if I buy a o2 locked(not cpw) 6s I could unlock with my own o2 account ?

Theoretically, yes, but o2 aren't unlocking the 6s yet iirc. You would have to use the phone for a while to associate it with your account and then request. It isn't guaranteed though, they could refuse. Even if o2 were to refuse there are eBay unlockers who unlock iPhones for a reasonable charge (again, only after o2 actually start unlocking though).

Far better just buying unlocked and not having the uncertainty.