Just did the treetop junior course today w/ my 2 kids - age 5 and 10. 5 year old was just tall enough to get onto the course so he was definitely the youngest I saw out there. I went on, too, to help him. We had a blast! The course is really adventurous for kids (and even for me as I am afraid of heights!) I think Go Ape did a great job of making it safe w/o feeling dull. The kids were really proud of themselves after finishing and were already asking when we could go back.