Thailand has long been known as a premier spot in the world for diving and snorkeling. Popular sites in the Andaman Sea (western side of the Thailand isthmus) include the Similan Islands and the Surin Islands, which are accessible by boat from Phuket. Richelieu Rock is one of the few places in the world to see whale sharks, while grey reef sharks are found near Hin Daeg and Hin Muang. Koh Bon and Koh Tachai are known for their manta rays, which may be found year round. Phi Phi Island is another spot where coral reefs can be enjoyed by the beginner or expert. In the Andaman Sea, the best time of year to dive is from October to April. The monsoon season makes visibility and accessibility to remote sites difficult. On the Gulf Coast, there are dive sites off of Pattaya as well as Koh Samui and many other islands. This diving is fun and adventurous, but not as acclaimed as the diving sites in the Andaman Sea.
Other adventuresome activities to be enjoyed in Thailand include whitewater rafting in the North and the northern parts of the Central region. The rainy season from June to October is the prime time to enjoy this sport. Tak, Mae Hong Son, Chiang Rai, Chiang Mai, Nan, and Prachinburi are some of the areas known for whitewater rafting. Some of these same regions also provide great places for mountain biking. There are organized tours available with guides and in some cases, back-up vehicles for those who need a lift! Thailand has a couple of rock climbing clubs and places to practice as well. For those interested, contacting the Bangkok Rock Climbing Club or the Thailand Rock Climbing Federation is advisable to find out the best information on where and when to climb. Trekking is very popular in the many national forests. In northern Thailand, trekking in the hill tribe regions is immensely popular. Some tours include elephant treks as well. Treks can last a few hours or up to a week!