That's because of its thick black plastic edges and physical buttons.
Oh yeah, and because the blue or gray camouflage backing is about as far from the S6's glass build as you can get (the black Active is camo-free).
These indentations all along the S6 Active's perimeter are also signs of its sportish independence.
One of the Active's best features is the blue convenience key (Active key) on the side.
A short press calls up the Activity Zone app, where you can access health apps and a flashlight. A long press opens another app, like your music player. Go ahead, reprogram them both all you like.
Keeping in line with the activity theme, the S6 Active can stand a dunk in up to 3 feet of water for 30 minutes. The S6 can't. (But the S5 could!)
Slightly wider than the S6, the 5.1-inch Active is a tight fit in some pockets, but if you're good with an S6, you'll be fine with the Active's size.
From left to right, the Galaxy S6 Active, S5 Active, S4 Active and Galaxy S5 Sport.
The Active series has always had more distinctive backings. From left to right: S4 Active, S5 Active, S6 Active and S5 Sport.