How to give a iPhone for Christmas then use it that day?

I'm going to get my daughter the new iPhone for Christmas, she already has the 4. How can she be able to use the iPhone 5 as soon as she opens it Chritmas Day? Can we just put the sim card in, then use?

Well, you would have to take it to the carrier store depending which one you're with and get it activated to her number.

However, doing so might stop the services on her current cellphone. If you ever ground her, you could pretend to do so, then go and take her current phone and get the data transferred to the new one. Wrap up the newly activated phone, off of course and give it to her on Christmas Day. Just a silly idea: p

If not you might have to call your carrier.