Iphone 7 from USA to Europe

Any model will work on GSM carriers in Europe as long as it is unlocked.

The AT&T and T-Mobile models will not work on CDMA carriers, but will work on GSM carriers.

The Verizon and Sprint models will work on CDMA and GSM carriers, though its up to the CDMA carriers to activate the iPhone on their CDMA networks.

Please note that the iPhone Warranty is not international, and a U.S. iPhone will not be serviced under Warranty in Europe.

Also read the following thread before buying anything as it illustrates what can happen if the iPhone is not unlocked:

iphone se sim not supported

The best advice is to buy the iPhone in the country you intend to use it in to avoid any issues with it.

When I was in Europe visiting, I found that my carrier: T Mobile did not charge me for data or text at all. I use an iP6s at that time and found it very useable with my US number...

I was on the GSM towers with T Mobile and since they are partners with other country's GSM - no charge - was a nice surprise when I got home with no extra charges....

It's a shame that the new iP 7 does not do both GSM and CDMA like the 6 and 6s did.

BTW: Other carriers - they charge a lot for use of your US number in Europe - my GF was charged $40 for international data use on her ATT phone! So just do what others have done - go get yourself a data SIM card when you land in any European country and use texting and data for pennies.... Of course it will not be a US number...