Here at Scubafish, we are very fortunate to be situated in extremely close proximity to the beautiful Ko Haa island group. In fact we are the only dive operation which, during high season (mid Nov- mid April), departs from Kantiang bay on the southwestern end of Ko Lanta. This means we have the shortest non speed-boat journey times to and from the islands and are often the first divers at Ko Haa each morning, allowing us to enjoy the first dive of the day at this unique and unspoiled location in relative solitude.
‘Ko Haa‘ literally translates to ‘Five Islands’ and yep, you guessed it, there are in fact five islands in the archipelago, each surrounded by reef systems and each with its own unique topography and seascape. The islands of Ko Haa are in fact karst limestone outcroppings, meaning they are riddled with caves and tunnels formed by rainwater erosion. This results in a variety of swimthroughs and underwater cave-systems, many of which can be explored by divers of all levels and some only suited to the more experienced.
The Chimney, located on the south side of Ko Haa Neung, is, as the name suggests, a vertical swimthrough. The deepest access to it is at about 16m and there are two shallower access points both at around 5m depth. The Chimney can be dived from top to bottom or bottom to top with equal ease, but my personal preferred approach is to swim upwards from the deeper access point.
Entering the chimney from the bottom for the first time can be a little daunting for some, as the interior can appear forbiddingly dark compared to the outside. But once a metre or so inside, your eyes will quickly adjust and the interior of the cave is easily visible without the necessity for a flash-light. This is also helped by light coming in from one of the shallow access points about 10m directly overhead.
The interior of the chimney is commonly filled with hundreds of small Sweeper fish (Pempheris sp.), the eyes of which will reflect the light from above back at you like a myriad of tiny stars. Pausing at this point gives great photo opportunities of the swaying mass of sweepers and a chance to scan the walls for less conspicuous animals such as nudibranchs, cleaner shrimps and crabs.
Continuing up the chimney (slowly, of course) brings you to a fork where you have two options. You can either continue swimming vertically up through a hole which will bring you out onto the reef at 5m, or you can branch off horizontally into a 4m long passage. The horizontal passage is slightly narrower than the rest of the chimney and is recommended only for divers with excellent buoyancy control.
Those who do choose the horizontal route, however, will emerge into an open sided cavern often referred to as ‘The Fish Bowl’. Here, day-light streams into a relatively roomy overhead environment from large holes in the walls, and divers will often find themselves floating among large schools of Five-line snapper who take shelter from predators in the cavern and feed off the currents that run through it. Also commonly found in the Fish Bowl are Robust and Ornate Ghost Pipe-fish, giant puffer-fish and a variety of flamboyant nudibranchs.
From here there are two options for exiting back onto the reef. One is through a relatively small swimthrough beneath boulders that have fallen from the cliffs above. The other is along a kind of miniature canyon which brings you out onto the reef wall where you’ll be confronted with hunting Blue-fin Trevally, schools of Barracuda and vast beds of swaying anemones, sheltering Clownfish, skunk anemone-fish and juvenile Dascyllus.
The Chimney is just one of many interesting and unique formations to be found at the Ko Haa archipelago. Ko Haa is part of the Mu Ko Lanta National Park and is open to divers and snorkelers from Oct 15th to March 15th yearly. Commercial and recreational fishing is forbidden in the archipelago.