Stonehenge offers dives the chance to undertake some good deep diving in the Similan Islands and offers swim throughs and many rock formations to explore at deeper depths. This dive site in the Similan Islands is a challenging dive site that gets its name from the group of granite boulders that are found on the sandy bottom. The reason the dive site is challenging is that it sits in an exposed part of the ocean and so there are strong currents that can mean divers become disorientated or use up their air too quickly. The site also has some deep parts to it, which also should be avoided by inexperienced divers. The boulders offer experienced divers a great dive with some good swim throughs and as it is a challenging dive, it is normally not as busy as dives in other parts of the islands.

To get down to the boulders, which sit at 24 meters, divers should descend using a mooring line. The boulders many nooks and crannies can then be explored. There is a good mixture of both hard and soft corals with many whip corals and Gorgonian fans, as well as anemones housing anemone fish.

Reef fish are in abundance and include wrasse, butterflyfish, triggerfish, boxfish, lionfish, and scorpionfish. Larger fish include tuna, trevally, barracuda, and different types of reef shark. Leopard sharks are common here and Guitar sharks have been spotted on occasion.