An Amazon listing of a screen protector for the S8 Active has touted an August 1 release date, so we have reason to believe that the device will be launched in that period, too.
https://www.notebookcheck.net/Samsung-Galaxy-S8-Active-may-launch-by-the-end-of-July.235582.0.html
Can't wait for it to come out. I'm about ready to upgrade my s6 active.