US iPhone 5S working in Europe

[greenorange12]

Hello!

At the moment I am working in Europe, but going back to live in US. It's so does happen that next month I am travelling to US for work, and I want to buy a USED iPhone 5S 32GB.

My iPhone 4 from AT&T works just fine in Europe, but this far I wasn't able to get clear answers about iPhone 5S:

-I have 'heard' iPhone 5S from AT&T will work in Europe, has anyone tried this?
-Does anyone know of a phone provider which iPhone 5S also works in Europe?
-If I bough iPhone 5S previously from AT&T- do I need to unlock it?
-If I bough iPhone 5S from any provider- do I need to unlock it?
-Would US iPhone 5S work on 4G network?

Thanks much for your help!

 

[T5BRICK]

Read up on LTE(4G) bands. No phone sold in the US supports ALL of the bands used throughout Europe, although some support most.

http://www.everymac.com/systems/apple/iphone/iphone-faq/differences-between-iphone-5s-models.html

The AT&T model will possibly need to be unlocked. Apple sells a "Sim Free" unit that is carrier unlocked. The best model to buy(in the US) is the Verizon model. It is fully carrier unlocked AND it works on AT&T, T-Mobile in addition to Verizon. All of these models support the same bands, which include MOST(but not all) of the European bands.

 

[greenorange12]

The link is very helpful, plus thank you for clarification. I will look into Verizon iPhones. Thanks again!