This cluster of underwater boulders is located off the south east coast of island 3 (Koh Pa-Yan), next to Shark Fin Reef.

Pinnacles in Boulder City lie 30 to 40 meters away from each other and the tops of the boulders are submerged at a depth of 12 to 18 meters.

Boulders lie on a sand bottom, at a depth of 35 to 40 meters.

The majority of the surface area of the boulders is covered by soft corals as well as some huge sea fans.

Clumps of staghorn coral are also scattered around the boulders.

Fairly strong in the direction of north to south and vice versa.

The marine life here is truly diverse and is similar to that of Shark Fin Reef.

Sharks sometimes can be spotted around the sand bottom around the boulders.

You can also see napoleon wrasse, humphead parrotfish and turtles as well.

Big groupers, snappers, angelfish, unicorn fish, boxfish and pufferfish can all be found dwelling around the boulder cliff.
Some smaller creatures such as pipefish, fire gobies, boxer shrimp, and dancing shrimp can be seen inside cracks and underneath rocky clusters.

Lastly, you can sometimes see big pelagics such as manta rays cruising around the vicinity.

This dive site is suitable for experienced divers because of the depth, 12 to 18 meters at the top of the boulders, and also because of the strong current.

In some cases to avoid decompression dives, divers may need to swim against the current in mid-water between the rocks because the depth to the sand bottom is sometimes too deep.

To avoid this situation divers should swim close to or behind rocks to avoid strong current.

You may consider mid-water diving against the strong current a good exercise, but this would be more of a dive for survival than for recreational purposes!

Overall Boulder City is great for a first deep dive in the morning.