I purchased the LG Watch Sport from BB with no intentions of using it on AT&T. I removed the AT&T sim and replaced it with a T-Mobile sim. I'm using a T-Mobile One Unlimited Data Phone Line Nano Sim. If you don't have extra lines, you can use T-Mobile Digits and just say it is a Gear S3 when you fill out the info online. T-Mobile will send you a sim that will spoof your cell's number, and it is free while in beta. It will not work on a T-Mobile wearable line. People are complaining about battery life, but I think it is perfectly reasonable to expect a full day of usage, and then have to charge it every night (just like a phone). With LTE off and everything else enabled, I left the house at 8am and had 35% battery remaining at 10pm. Thats 14 hours on my wrist and less than 2/3 of the battery was used. Another 7 hours to drain it completely is fair, do I really need 21 hours of usage straight? No. I plan to only turn on LTE when I don't have my phone. After reading reviews, I thought this watch was going to,be laughably large, and it isn't. I am 5'10" and 185lbs but have small wrists and I think it's perfectly sized (maybe a little thicker than most would choose but I got used to that in a day. There is room for improvement in regards to battery optimizations and stuff, but it already seems like a mich better OS than Tizen, and it just got released.