Koh Libong is known for the dugongs that are sometimes called "sea cows". It is protected species of marine mammals thats looks like dolphins even if their line is less elegant. I'm not a zoologist but they make me think of seals with a dolphin's tail. You can observe dugongs by taking a longtail boat and go little off the island.
The best time to come to Koh Libong 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 Libong and other Trang islands are closed.
There are no ATM or exchange office in Koh Libong, so it is necessary to come here with enough cash to cover your expenses. In low season (from mid-May to October), tourism activity already quite low in high season is almost non-existent.
I admit it's a bit subjective, but Thai Smile is my favorite airline for domestic flights in Thailand. Unfortunately, they are often more expensive than Nok Air, Air Asia or Thai Lion Air (and it is justified because quality and especially onboard...