T-Mobile is now rumored to launch a Samsung Galaxy S8 Active variant sometime in the future. If you've followed the Galaxy S Active line of devices then you'll know that the device series has been available on AT&T exclusively for every iteration, and up to this point that includes the Galaxy S8 Active. That all appears to be changing though according to Evan Blass, who also notes that there is no information at this time on an actual release date or pricing availability. That said, the Galaxy S8 Active costs $849.99 on AT&T so it's possible that the price on T-Mobile will be close to this price point, if not a bit under given that T-Mobile is usually less expensive on hardware in addition to its plan costs.
As for the launch time frame, without any detail just yet on when the phone is expected or rumored to launch, the U.S.' third-largest wireless carrier may not have the device in stock and ready to sell to customers for months. It could launch anytime between now and the end of the year or T-Mobile could end up launching it in the beginning of next year, there's just no way of knowing at the moment. However, With the beginning of October coming up in just a few days it's starting to reach the holiday shopping season, and having the phone ready to go before that time ends would be a good move on T-mobile's part.
The T-Mobile variant of the phone is said to come with a model number labeled SM-G892T, which is essentially the same model number as the AT&T version save for the letter T, where AT&T's ends with the letter A. T-Mobile often puts T at the end of the model number for its variants of devices, and this isn't uncommon for other carriers either as AT&T and Verizon do this for many of their phones as well. In addition to a T-Mobile variant, Blass also suggests that another model of the device could be available in the future, highlighting a model number labeled SM-G892U. This could mean that the device will be available as an unlocked or universal variant at some point meant for use on other carriers. For now, though, it's unclear where this version of the device might be headed.