HT4972 Can I use iPhone 5 in Europe?

Question

I am going to Italy and would like to know if there is anything extra to do to use my new iPhone 5 for phone and/or data.

Answer 1

1.  No, because if you have an iPhone on AT&T, the LTE frequencies are different between the US and Europe and if you have an iPhone 5 on AT&T in the US, then it will be carrier locked to AT&T and that is a different model to the other European model, so the best you can hope for is to use the international roaming feature and link into an Italian 3G network.
2.  There are no unlocked iPhone 5's available in the US at the moment, but when they do become available, it is the other model that is available, so unlocked means unlocked and it does not matter which carrier you use.  That is your choice and you can use any one that you want and you should also be able to swap nano sim cards and use local ones whilst travelling.
3.  If you purchase the unlocked model of the iPhone, which is a different version to the US carrier locked, then you have a better chance with LTE frequencies.  Obviously there are going to be differences between countries because their LTE frequencies are different.
Well no, of course it cannot be truly a world phone because every single country in the world is different and all countries are in different stages of development of their 3G capabilities.  There is no one frequency at the moment for all countries.  There may possibly come a time when this is so, but not at the moment.