About 70% of Koh Kood is covered by ancient tropical rainforest with Klong Chao Waterfall or (in Thai) Nam Tok Khlong Chao in the center. The Klong Chao Waterfall flows throughout the year and offers a nice swimming spot.
It’s actually quite a famous waterfall as His Majesty King Rama VI visited the waterfall in 1911. He named it Nam Tok Anam Kok to commemorate Ong Chiang Su, a Vietnamese king taking refuge in Thailand in the late 18th century.
The waterfall is easy to reach. Just rent a motorbike or bicycle and follow the signs or rent a kayak and paddle up the Klong Jao River, the trip is worth it! You’ll know it when you get there, because by kayak you can’t go any further. Kayaks can be rented at several accommodations along the Khlong Jao River.
The entrance is free and from the road to the waterfall is a short jungle trek of about 10 minutes with a clear path to follow. Near the wooden sign and exit to the left is a small temple on the right where often monks are meditating.
Many resorts offer trips to the waterfall or can organize a (private) trip. Most package tours include a trip to the waterfall and most of them go there in the afternoon.
No shops around (yet) so if you plan on staying a while which you probably will it’s best to bring some drinks.