We discovered this island while out on a snorkeling trip from Koh Chang. We had planned on moving from Koh Chang directly to Koh Mak, but after stopping and discovering the amazing snorkeling in the area, decided to stay on Koh Wai. We liked this island better than Koh Chang, since Koh Chang had huge waves, and they advised against swimming in low season due to riptides. Koh Wai was the absolute best place for snorkeling, which is our #1 favorite thing to do while in Thailand. We have been to Krabi, Railay, Phi Phi, Jomtien, Koh Samet, Koh Chang, and about 5 different places in Phuket, and we thought this was better for snorkeling than all of them. Oh Koh Wai you could actually walk right out your door and have an abundance of coral and fish to see. Of course Phi Phi has fabulous snorkeling as well but you usually have to get a longtail boat to take you there. There are also great snorkeling places a short boatride away from Koh Wai. We rented kayaks 2 or 3 days and made our way around the island....definitely worth it! The rooms were very very basic. Don't expect anything fancy about your room, it's basically a concrete bungalow with matresses. The rooms were big enough for a family of four, which is also a selling point for us, as we travel with our two young kids. come for the island and the snorkeling and the crystal clear waters and the friendly staff. Rent a kayak and explore the island and the powdery white beaches around it.
There are only three hotels on the island, and one of which was closed for low season, so we saw maybe 10 other tourists staying on the entire island while we were there, which is just what we wanted. So we actually enjoyed the one-hour of bombardment from daytrippers (which we had just been a few days prior!) We considered it our daily entertainment!
We thought the food was really good at the restaurant, and extremely affordable. I'd expect higher prices being on a tiny island, but prices were equal to or less those in more populated areas.
In summary: 5 stars for location and the island as a whole, 2 stars for hotel rooms.