Following in the footsteps of Virgin and Boost Mobile, both of which launched it in January, AT&T is going to be selling Samsung's Galaxy J3 (2016) at some point in the future. We know this because serial leaker @evleaks has outed the official press renders of the device, complete with AT&T branding on the back. It's unclear if the carrier will offer the phone in more color versions or just this white/black combo. As you can see, the name on the handset's back is something along the likes of Galaxy J3 6, or J3(6). So it will be interesting to see what AT&T's promotional materials...
Source: http://www.gsmarena.com/samsung_galaxy_j3_2016_for_at_t_gets_pictured_in_leaked_renders-news-17226.php