For an inland adventure, head to any of Ko Samui’s waterfalls. The best known one on the island is Nam Tok Na Muang. There are actually two waterfalls in this area labelled on maps as Na Muang 1 and Na Muang 2. The first waterfall is relatively easy to reach, but the second waterfall requires more effort and the rocks there can be dangerous. Most visitors opt to just enjoy swimming and relaxing at Na Muang 1.

Cr. https://fanclubthailand.co.uk/25-of-the-best-things-to-do-on-ko-samui/