On the island there si a famous cave, the Emerald Cave or Tham Morakot in Thai. You can only enter from the sea by a long tunnel before reaching a skylight with a beautiful beach. This palce is on every tour of local travel agencies causing a major ballet of boats from neighboring islands, Trang and Koh Lanta. it distrubs a little the peace of this small island full of charm. To really enjoy Koh mook, you have to stay for at least one night. Personally, I recommend the Charlie Beach Resort , the largest complex on Had Farang. There you will find everything you need (bungalows of different categories, kayak, scooters and bikes rentals, a small swimming pool, massages on the beach, a restaurant, a supermarket ...).
The island is very popular at the end of the year. If you plan to get there at this time, it is better to book your room in advance ! There are no 7 Eleven on Koh Muk island, just 2 or 3 little supermarkets around the pier and one at Charlie Resort on Hat Farang. There are only 1 ATM on the island so get enough money to stay here.
The best time to come to Koh Muk is from December to March knowing that during the low season from May to the end of October, when it rains the most, tourism activity is very limited and most of the resorts on Koh Muk and other Trang islands are closed.
We are one week away from Chinese New Year (January 25th, 2020) and despite a lot of mail and detailed information requests from various Tourist Offices in several cities, I unfortunately did not get all the details that I would have liked...