Checking phone dimensions and button/camera placement will give you an answer no matter what phone case you wonder will fit your phone. And if there is a store near with cases for s8 then you may possibly try them there.
Ha, a case is not needed with active line for protection.
That is the whole idea for the rugged construction.
I have been using S8 Active with a wallet case.
This is not expensive and does the job well.
Only have to bring one thing now in my pocket.