I agreed to go on this tour for my friend, who's into rock climbing and generally way more athletic than me. And despite my lack of athleticism and even a fear of heights, I'm glad I did! I was only able to complete the beginner portion of the course, but given that it took a good hour, it still felt worthwhile. In fact, I eventually got past my fear of heights, and then it was just a matter of stamina. While my fight-or-flight instinct was kicking in like crazy up there, though, I can say I never felt less than completely safe. This was thanks to the very thorough briefing we got beforehand, on safety procedures and proper use of the equipment. The equipment, too, was sturdy and well-maintained, and they took care in strapping us into our harnesses. I also have to commend the extremely kind, patient guide who monitored us from the ground. After I'd bowed out following the beginner course, and was waiting for my friends to finish the advanced courses, he showed me where I could still join in on the ziplines - which were a ton of fun. The zipline course at the end made for a great icing on the cake, too. Finally, the driver from the local tour company, who brought us to the park, was courteous and safe, and the car was clean and new. Overall a great experience. Maybe not for the faint of heart, but even if you're at less than optimal fitness, you can probably finish at least part of the course - and feel pretty accomplished when you do. And my rock climbing friend said it was one of the highlights of the Phuket trip for her.