6P and AT&T question

Should be able to. I took my sim out of my Note 5 on Verizon and swapped it to my 6P.

Posted from the 6P of Aluminum Doom
 
They both use nanoSIMs, so yes. (That's the only thing you have to check, and GSMArena has the specs for all GSM phones (and a lot of CDMA phones too).
 
I believe Sprint is the only carrier where, for whatever reason, you have to physically get a new SIM card activated for use in the 6p, all other carriers just let you hot swap.

Posted via my Nokia 8210 from the inside of a Kitten.
 
I was able to use my micro sim from my Galaxy S3 with the 6P. I cut it down to size and it worked fine. It was much easier than dealing with AT&T not recognizing the IMEI number if I got a new SIM.
 
I would suggest that you also contact AT&T just in case and update your IMEI number. I wasn't getting LTE until I did that.

Posted via the Android Central App
 
Just so you know, you won't get HD voice or volte on AT&T. Other then that it works very well.
 
Screw ATT. I switched to Cricket long ago. Excellent service, cheap cheap cheap, and they use the ATT network and towers. Just my 2 cents.