Based on the model number (I9300), this SGS3 should have the Exynos 4412 Quad-core 1.4 GHz Cortex-A9 CPU and the following bands:

2G GSM 850 / 900 / 1800 / 1900
3G Network HSDPA 850 / 900 / 1900 / 2100
4G Network LTE (regional, you'll have to contact a Best Buy Mobile associate for more details on the exact 4G frequencies since they may vary from region to region)

-MrSamsung

Thank you for your interest in this Samsung Cell Phone. Although I do not have the information you requested, a dedicated Best Buy Mobile representative may be able to assist you better with this question. Technically, as long as the bands on the phone are compatible with the bands the service provider supports and the phone is unlocked, the phone will be capable of working on that carrier and in that region. Unfortunately, since I am not affiliated with any Service Provider, I cannot provide any additional information on what bands each carrier uses. Please click on the Customer Service link for more details or contact your service provider for more information.

-MrSamsung