This site is a further 1.5km south east of neighbouring Shark Fin reef. Although part of the same underwater ridge as Shark Fin, the main dominant feature of Boulder City are the huge granite boulders providing interesting archways and swim-throughs. Depths from 12 - 35m. Visibility 18 - 25m.
The site has numerous large sea fans, scattered hard corals, spotfin lionfish, jewel basslets, and blue spotted rays. You may also see bumphead parrotfish, Napoleon wrasse, and leopard and whitetip reef sharks. Large stingrays and whale sharks are also sometimes sighted.