1. Na Muang Waterfall is one of the most popular attractions on the island of Koh Samui in Thailand. It is located about 12 kilometers south of Nathon Bay and is named after the large purple rocks that surround the waterfall. \"Na Muang\" means \"purple\" in Thai.

There are actually two waterfalls in the area: Na Muang 1 and Na Muang 2. Na Muang 1 is the larger and more impressive of the two, with a cascade of water flowing into a natural pool where visitors can swim or relax. The waterfall is surrounded by lush greenery, making it a picturesque spot for nature lovers and photographers.

Na Muang 2 is a smaller waterfall located a short distance away. It is not as popular as Na Muang 1, but still offers a peaceful and serene atmosphere.

2. The waterfalls are open to visitors daily from 8:00 AM to 5:00 PM. There is no specific phone number available for the waterfalls, but they are easily accessible and can be found on most maps or travel guides of Koh Samui.

3. There is no entrance fee to visit Na Muang Waterfall. However, there may be a small fee for vehicle parking. To reach the waterfalls, visitors can hire a taxi or rent a motorbike or car. The waterfalls are located along the main ring road of the island and are well signposted, so they should be relatively easy to find.