A few of my friends are into adventure activities and one of them have actually started a small business organising adventure holidays in Malaysia. It’s called WHOA! Adventures. Although I have not tried it myself, but I’ve got a few feedbacks from friends who have tried and tested the adventure trips and there is no complains (as far as I know).
In addition to organising a wide range of adventure trips ranging from river sport, water sport, scuba diving, caving to mountain trekking, etc, they also look for the best location to held these activities. Thus you’ll also get to discover some of Malaysia’s best kept secret while doing the thing you like!!