Boulder city is a submerged site about one kilometre off the east coast of island no. 3 and about 400 m south east of Sharkfin Reef.
Due to its exposed location it is possible to see almost anything on this Similan dive including whale sharksOpens in a new window and manta raysOpens in a new window.
It is always an exceptional dive.
In March and April 2010 the Similan Islands suffered from a naturally occurring event called the Reverse Indian Ocean Dipole. This is very similar the “La Nina” that changes water temperatures and currents in the Pacific ocean. In this case, the water temperatures in the entire Andaman Sea were raised between 2 or 3 degrees above median. This was enough to damage the living corals in shallower sites and those with limited tidal interchange. On the Western facing side of the Similan National Park, the affect on the sites was minimal. On the shallow sloping reefs of the Eastern side , there was a more noticeable impact on the corals. His has caused some bleaching, and on two of this sites a – a noticeable impact. The National Park system shut down several sites throughout the Andaman region to protect the reefs from potential human impact (diving, snorkeling and fishing). These sites are already showing regrowth and at least two of the sites have re-opened at this time.
Plus understand that the bleaching is not the result of direct human impact, or over use. It is the results of vast climactic changes that are happening on our globe. The reefs are accustomed to these temperature changes and can easily adapt and regrow. They can not regrow from the damage done to them physically or chemically by inconsiderate divers and snorkelers.
As with all dive sites in the Similan Isiands, it is strongly recommended that you go with only registered and reputable dive operations, carry suitable travel insurance that covers diving accidents and evacuations as well as trip cancellations insurance due to the potentially erratic weather conditions.