Family phone swap

Depends on your carrier. GSM, swap the sim cards. CDMA you'll have to call in or can do it online.

 

GSM, swap the sim cards


I dont think you would be able to do this , because iphone5 will have smaller sim card.

 

Yep.

If the new phones use the same sized SIM cards you can just swap them and that's it, but it's looking like the new phone may have new smaller cards, so that won't work.

Just go into AT&T and tell them what you want. Since all the phones are AT&T iPhones they can do this with no problem.

When I sold my iPhone4 to my friend's wife to replace her 3G, we went to the AT&T store and they took out my 4's SIM, made a new one with her info, and put it in.

That was it.

 

That just takes care of the phone part, btw. Make sure you have backups in either iTunes or iCloud that are up to dates so you can wipe phones and re-load them as the proper versions with people's apps and settings and everything.