does the nexus 5x require a Fi sim card

[AC Question]

can i use a att sim

 

[hallux]

You can use a SIM from ANY carrier. If you bought the phone expecting to only pay $200 (or $250 if you got the 32 GB), you at least need to activate the Fi service it came with for a day, or put in an already-active Fi SIM card. That is one of the stipulations of that deal - that you activate Fi service on it within 30 days.