Much like the landscape, the underwater world in Thailand is rich in natural beauty and diversity. Claiming one of the top ten dive areas in the world and split geographically between two seas, Thailand's waters are also home to some of the worlds' largest pelagic creatures such as manta rays and whale sharks. Choosing the best dive sites, however, is not just a simple case of creating a list. Strong currents and deep waters mean that some of the most spectacular and memorable dives are reserved only for advanced divers with the right experience under their weight belts. With this in mind I have written this article from the perspective of a complete beginner and the order in which I would suggest tackling the various underwater wonders on offer.
First you have to learn to dive (assuming you are not already certified). Since on completion of your Open Water Diver course you are only qualified to dive in conditions equivalent to or better than those in which you learnt, it's probably advisable not to do your course in completely idyllic conditions as these will then be difficult to replicate. This makes the Northern Gulf of Thailand a perfect place to start. The visibility is generally not as good as the south and experience of tidal current can be introduced gradually under controlled conditions, although in terms of marine life there is still plenty to see.
As a newly certified Open Water Diver I would suggest that your next port of call be Koh Tao. The easiness of the dive sites here combined with the relatively good visibility and quality of the reef make it an ideal place to further your experience. There are over 30 dive sites all within a maximum distance of 45 minutes by boat. Twin Peaks and Green Rock are notable starter sites with plenty of variety in coral, sponges and tropical fish and minimal current to boot. As your underwater ability increases you will want to try more adventurous dives such as the renowned Chumphon Pinnacle where you may be lucky enough to encounter grey reef sharks bigger than you (although quite harmless) and Sail Rock with its underwater chimney rising from 18m all the way to the surface. Both of these sites are regularly visited by whale sharks and are a must see.
As we move further south it may be a good idea to consider an Advanced Open Water certification (again assuming you are not already there) in order to fully appreciate the exciting new spots. From Phuket you can reach many of the best places including multiple sites around Racha Yai, Racha Noi, Phi Phi and various other outcrops and islands. Shark Point; Anemone Reef and Koh Ma number among the more gentle dives and they are blessed with an amazing array of underwater flora and fauna, whilst King Cruiser makes for an unforgettable wreck dive. Leopard sharks and turtles are common here as are stingrays and the more discerning can spot seahorses and frogfish and all different kinds of moray eel. For the really large pelagic encounters you cannot miss.
South Pinnacle (Raya Noi) and Hin Daeng & Hin Muang. These are not for the faint hearted and I would recommend an absolute minimum of 20 dives before attempting them. On my first dive at the Pinnacle I saw absolutely nothing (apart from huge manta rays) and I breathed my tank dry in 27 minutes (I have been diving for 20 years). This is how strong the current can be. The two Hins (Hin Daeng & Hin Muang - red and purple) are so called because of the colour of the soft corals that adorn them and are considered the jewels of the South Andaman. Whale Sharks and Manta rays love these places almost as much as divers do. It's not difficult to see why. Even when the gentle giants are absent the spectacular drop offs, amazing visibility and sheer volume of marine life tantalize the senses. Again these places are not to be missed, but require a certain skill in order to be fully appreciated.
Now you are ready for the Similan Islands and Surin, the ultimate in Thailand's diving inventory. Although there are many dive sites here suitable for novice divers, as usual the best ones tend to be deep and subject to strong current. Big fish, I'm afraid, just love strong current and once you get used to it so will you. The best way to see them is on a three to five day liveaboard cruise, and it would be a shame to shell out the money for this if you cannot enjoy it to the max.
In the Similans, Christmas Point is a dramatic series of underwater pinnacles and canyons. Here you'll find an explosion of life in the soft coral gardens; parrotfish, lionfish, wrasse and groupers are all common. There are often big jacks on the hunt here and you may glimpse white tip sharks prowling. Elephant rock is unsurprisingly named after the bulbous looking rock formation. This dive site is one of the best around. Below the surface it offers gigantic stacked boulders and a labyrinth of swimthroughs, arches and caverns. Marine life is abundant and huge schools of yellow goatfish and snappers can be found around the deeper levels. Turtle Rock is an impressive series of submerged boulders and swimthroughs in typical Similan fashion. Surrounded by coral and marine life this is one of the better places to spot turtles. Encounters with eagle rays are not uncommon.
Moving towards Surin, Koh Bon features one of the only vertical walls in Thailand with depths of over 40 metres. Leopard sharks are common on the ridge and on the sandy flats below the. The soft corals here are radically different and include shades of turquoise, yellow and blue, besides the more common pinks and purples. Koh Bon is one of the better places to see manta rays, especially towards the end of the season. Koh Tachai has an offshore underwater ridge that runs perpendicular to the island and is considered to be one of the finest dives in the Kingdom of Thailand. It is famous as a place to see larger animals such as rays, leopard sharks, nurse sharks and hawksbill turtles. Richelieu Rock is Surin's ace card. It is a small submerged rock about 18 km east of Surin and rates as one of the best places in the world for swimming with the whale shark. For some reason, Richelieu Rock attracts more than its fair share of these graceful animals.
If by now you have the impression that manta and whale shark sightings are commonplace please accept my apologies. Such encounters although frequent remain a privilege and an honour and the animals themselves choose when. Also in the world of diving no two days are the same. Keep an open mind and accept that everything is subject to the laws of nature and you will not be disappointed. That said, the more often you dive these places the better chance you have, by the law of averages and the more you dive the better diver you become. So where does it go from here? Well, you may have noticed that Bangkok sits right in the middle of Southeast Asia, which arguably makes it centre of the diving universe. It gets better. Good Diving.