Plitvice Park

Both times I visited Croatia (visited Plitvice on each trip), I took only a single pair of shoes for my entire trip: once I wore "walking shoes" and once running shoes (which I now wear pretty much all the time). They worked just fine for me in the park. The trails at Plitvice aren't especially difficult. In fact, some of what you walk on are man-made wooden boardwalks. It's a fairly developed park.

So yeah - if you will already have comfortable shoes for the rest of the trip, wear them in Plitvice too. That said, if you happen to get a lot of rain (I was lucky on my visits - no rain), it might get a bit muddy walking in the park.

I'm female, but it sounds as if I wear the same type of shoes Andrew does, and you may be planning on something not quite as sturdy.

I didn't encounter any difficult stretches on the trails, but there can be fallen leaves (slippery when wet), and the paths on the ground--as opposed to the boardwalks--aren't totally flat and smooth. Still, I have a lot of issues with uneven rural paths, and Plitvice did not make me nervous in that regard. It was the massive crowding during day-tripping hours and the lack of railings that had me wondering whether I'd end up in one of the lakes. I didn't, but it required some concentration that I would have preferred to focus on the beauty around me.

Any sort of normal shoes will work. I typically wear sneakers/tennis shoes/running shoes (depending on where you're from and how picayune you are). They're fine in the park.

Wear anything you want that's more substantial than flipflops and you'll be OK.

Not necesarily something sturdy, but something that won’t be slippery in the wet is what you should be going for.