According to the product specs tab: Material: Suede with faux crocodile trim
I wondered the same before I bought this bag. I bought the leather version, not the suede, but the trim is the same. Although the product description on Sierra is vague, I looked elsewhere online and found it described as "polished faux crocodile leather". When it was brand new, it was hard to tell if it really was leather vs a synthetic, but now that it's getting broken in, it feels and looks more like leather.