Trails ae not bad. People have even done them in those tiva sandals. But personally I wouldn't want to twist an ankle while out there so it's hiking boots for me.

I would certainly use hiking boots-and long socks or pants-the catch-n-keep can be brutal on the skin. Also some of the terrain is rocky and it certainly is easy to twist an ankle.

I have hiked quite a number of times on St. John on various trails (Reef Bay being one of the more diifficult) almost always in a good pair of sneakers... a couple times in Tivas (that was the Caneel Bay, Cinnamon Bay, Soloman Bay, Drunk bay trails - and the tivas were Ok - but between sweating, dirt, sand, salt water between the foot and sole it was not comfortable. Sneakers would be my suggestion, strong, light, comfortable sneakers. As for clothing, shorts and a t-shirt, swimwear underneath if you are hiking a trail that ends up at a beach. Almost all the trails are maintained and they are clean and clear of the foliage... if you are hiking through and getting caught up in trees then you probally are not on a trail anymore. A few trails are not maintained well - and these few have notes saying such on the map of the trails that the park service gives you at the Visitor Center so if you are going to those - a light pair of pants would work. I have only wished I was wearing pants once when I hiking on St. John... and it was because I choose to ignore warnings not to climb on ruins and I did and fell, and fell into sting-a-nettle (which is a vine that causes itching - sort of like poisen ivy...). Light pants are fine, maybe keep a pair of shorts in your back pack or vice versa... so that depending on environment and temperature you can change if you need to. Bring lots of water!! Sunblock too. Have a great time.

--Islander