Racha Yai Island

Racha Yai Island is located approximately 30 kilometers south of Phuket. Because the island can be reached very quickly and its dive sites offer a wide range of depths, this island is very popular as a day trip destination for both beginners and professionals in diving.
Depending on the wave direction, diving usually takes place on either the west or east coasts.
Bungalow Bay
The dive site Bungalow Bay, or Ao Patok, is a popular spot during the high season from November to May. The bay features a wide white-sand beach and beautiful rocky cliffs where you might see wild goats watching the arriving tourists.
Moving along the southern or northern walls of the bay, you can encounter large schools of small fish, moray eels, lionfish, and other marine life. The walls are covered with hard corals. Also along the southern wall, towards the exit of the bay, you can see an artificial reef made of concrete spheres. And a bit deeper, around 9-10 meters, there is a mushroom-shaped coral formation with a small swim-through cave at its base.
In the central part, at shallow depths, there are several reefs where barracudas are often spotted. And a little deeper, where the bottom becomes sandy, you are sure to encounter stingrays hiding in the sand.
The depth of the bay increases from the shallow beach area, reaching 20-25 meters at the bay's exit. And if you continue further out, depths can exceed 40 meters.
Bay 1 and Bay 2
The dive site Bay 1, or Ao Lah, is located on the east side of the island. In the shallow part, from 3 to 9 meters, there is a large coral reef inhabited by a great variety of fish.
Deeper, in the sandy zone, lies an artificial reef made of concrete cubes and spheres. This reef was installed relatively recently, and under certain conditions, you might think they are remnants of a ruined city. Also among the concrete cubes, lionfish and triggerfish are often found. And beneath the cubes lie huge sea cucumbers, which can reach up to two meters in length.
Further out to sea lies the Haruby Star wreck. The bottom of the wreck rests at about 20 meters, while the top is around 14 meters deep. You can easily swim inside the wreck, but be very careful, as moray eels can be found inside.
Siam Bay
On the north side of the island is the Siam Bay dive site.
In my opinion, this dive site doesn't boast the huge diversity of marine life found at the nearby Bay 1 and Bungalow Bay, but it has its own advantages compared to the others.
Large dive boats visit here less often, resulting in fewer crowds on the surface and underwater. There are several very large gardens of soft and hard corals here. On the sandy part along the shore, you can find coral farms scattered here and there. Artificial metal or concrete structures where various types of corals are attached. They become habitats for a large number of small fish.
In the center of the bay, at depths of 20+ meters, artificial reefs in the form of life-sized elephants, as well as warriors in traditional armor, have been installed. They have all long since toppled over due to strong currents and storms, but they still present an interesting sight.
The underwater inhabitants are not as accustomed to divers, so they are much easier to scare off, therefore, you need to be extremely careful when taking photos or videos.