Diver with Gorgonia Seawhip at Boulder City
Diver Gorgonia Seawhip

Boulder City is an additional totally submerged Similan Islands dive site, only noticeable by several red buoy markers. The dive site is a bout three hundred metres away from Similan Island number three.

There are nine islands I total in the Similan’s and islands number’s one, two and three are close to everyone in general for conservations reasons.
Boulder City and Shark Fin Reef are the closest that we can get to the three islands; they have been shut since I can recall. These three islands are closed to the general public and they have become more of a Turtle reserve, due to the hatching program and reef preservation.

Boulder city is a series of large granite boulders distributed, and then there are many other smaller sized boulders sprinkled about the dive site, with much of sandy areas housing attractive coral beds. The currents can get very fast here at particular times of the month, so a good tide table is worth referring to before diving.

With strong currents you have get more voracious action from fish such as Barracuda’s, Trevallies, Dogtooth Tuna’s and Spanish Mackerels.

Boulder City – Excerpt from Dive Butler’s logbook

Dive Mike behind Gorgonia Fan at Boulder City
Dive Mike behind Gorgonia Fan

At Boulder City the vis is around twenty metres or more, we were unquestionably blessed as there was only a slight current. Boulder city is one of the more difficult sites here in the Similan’s and there are few places to shelter should the current start to lash up.

We dropped to about fourteen metres, which is as shallow as it gets here, and immediately we could see a slumbering Leopard shark, well it looked asleep, however as we advanced on it to take some pictures, it gradually lifted from its inactivity and with a moderate flick of its long tail fin it was gone.

Advancing along the reef we came upon a Blue Fin Trevallies squad which had laid a siege upon a big school of the tiny Baitfish, there were only ever going to be one set of winners here. Out of nowhere a Great Barracuda virtually two metres in length appeared, the utter size of this superb specimen was sufficient to increase the air intake of a mermaid.

As we made our way round this distinct site we came upon, three Cuttlefish, they were practically unaware to our existence, it is not unusual for cuttlefish to be seen in three’s this way, particularly if it is breeding season. So we observed from a suitable distance and then carried on our saunter around Boulder City.

It was unquestionably our lucky day today, just as we started to go up to our five metre safety stop, a Manta Ray glided a four metres specimen, she gave us several fly byes then she was gone. What a great dive, we are unquestionably coming back here soon, superb.

Boulder City is open for scuba diving from November to April and frequently visited by Thailand Liveaboards and dive day trips from Khao Lak.