Diving in Thailand is best enjoyed on a liveaboard boat. These boats are mainly based on the country’s west coast, around Phuket, Phang Nga and Ranong, and they offer liveaboard diving trips of various lengths and at a wide range of budgets. The Similan Islands, Koh Bon, Koh Tachai & Richelieu Rock are where most of them visit from October to May each year. Nearly all of the Thailand liveaboard diving boats have air-conditioned cabins for guests and offer up to four dives per full day. Some have private en suite bathrooms, and others try to focus on value. Almost all are professionally modified or purpose-built for scuba diving liveaboard trips. In contrast to Koh Tao, Phuket and Koh Phi Phi, where day trip diving is more popular, Phang Nga’s Similan Islands & Richelieu Rock are quite far out at sea, and there are more than two dozen world-class diving sites condensed in a relatively small area. Therefore, the best way to dive in Thailand is to join a scuba liveaboard cruise and stay out at sea for a few days. Two days and one night is enough for those who want the liveaboard diving experience but want to limit costs or time sleeping on a boat. But the most popular trip length is three or four days & nights, enabling divers to visit all of the best dive spots in Thailand. And for the early morning and sunset or night dives, there are very few other boats there because the day trip diving boats either haven’t arrived yet or have returned to Khao Lak.