SIM cards & old and new phone

[MyNameIsJane]

Hello, I’ve just received a new iPhone with a different contract. I don’t necessarily want to use the new phone straightaway. Can I put the new Sim card into the current iPhone and cancel the old contract? I’m still with O2.

Apologies - posted too soon! Thanks in advance.

You can as long as it's the same size SIM. All iPhones since 2012 (iPhone 5 and upwards) have used nano SIM cards.
I don't know why you wouldn't want to use a brand new iPhone straight away though.

Thanks! I got it set up. The new set up to transfer from iPhones has really improved. It transferred everything over to the new phone which is now away and ready for the proper unboxing next month.

The reason I’m not going to use it straightaway is that it is going to be a birthday present. My dd1 will then have my old phone and dd2 will then get dd1’s phone (without a SIM) as it’s her birthday too.