This is an easy dive, with nice and easy currents, and it is suitable for beginner divers. Waterfall Bay gets its name from the nearby waterfall on the island near the reef. It is located in a bay in Koh Similan Island and is a gentle slope that goes down to a maximum depth of around 20 meters with patches of sandy bottom amongst the reef. There are some rocky formations on the bottom as well as a good mix of soft and hard corals. The rocky formations consist of some boulders that add variety to the dive.
The hard coral includes staghorn coral, brain coral, and pore coral in abundance. These continue all the way down to another dive site further north, Turtle Rock. Many of the usual reef fish can be spotted here and many smaller creatures such as boxer shrimp, flat worms, and anemone crabs can be spotted.
Close to the boulders, reef sharks and the rarer shovelnose ray have been spotted on the reef whilst turtles are very common on the reef. The site is a common night dive as it has a large number and variety of crabs, shrimps, and lobsters. Night divers can also spot mucous cocoons containing parrotfish that are hiding from night-time predators.