Iv got a new iphone 5 which i got on EE.

i want to use a three sim card in there.

Im i right in thinking if i put my three sim card in there the iphone will lock onto 3 and wont work with any other carrier

You will need to get EE to unlock it and then you can use it with any network

so its locked to ee already.

and it isn't locked to the first sim u put in.

If it came from EE then it's already locked to EE

thanks