Thailand – Australia – United Kingdom

TDI Cavern Expedition Course – Khao Sok National Park

by Christos Kardana

It’s easy to get excited about Khao Sok National Park. Astonishing areas of ancient rain forest, exotic rare wildlife and countless trekking routes provide the ideal setting for the avid explorer or outdoor enthusiast. It also provides the perfect backdrop for diving fanatics such as ourselves here at Big Blue Tech, were we are all about going ‘deeper and darker’.  Khao Sok National Park’s 165kmsq lake – created by a damming project in the early 1980s- provides a rare and challenging environment for advanced divers. The lake is mesmerising, with limestone sheer cliffs and pinnacles surrounding the immense body of water. The water itself is a layer cake of debris covered surface, sulphur induced mid water columns and finally crystal clear water engulfing submerged tree tops at 60m in what can prove to be the most serene and yet challenging diving site for many. Big Blue Tech returned to this favourite destination to conduct the August TDI Cavern Course, in what was our first visit since our successful Technical Temple Expedition back in June.

Cavern and cave diving is an exhilarating experience appealing to a wide array of divers from speleological fanatics exploring the limestone formations formed over years of natural weathering and water flow erosion to hardcore divers looking for the challenge of extreme dive exposure and expedition planning and logistics.

The Big Blue Tech TDI Cavern Course is a 4-day expedition with fee covering all costs involved during the length, including overnight boat and minibus transport there and back, food and drink cover and the certifying course and additional dives as well. The TDI Cavern course is the first step in overhead environment training covering all necessary skills for chamber diving within an ambient light source putting you on the road for full cave diver in the future if your up for the challenge. Starting at our home headquarters in Koh Tao it’s a simple and pleasurable journey to the Khao Sok National Park resort.

Surrounded by evergreen forest, flowing streams and peacocks, academic presentations and theory Q&A is covered followed by hands on practical reel work including tie-offs and placements, team diving contact drills and light and air source failure bail out techniques.

Day two means we can finally get in the water and after a delightful traditional long-tail boat ride through the lake; a full skill briefing is conducted before kit up, entry and penetration of our main training cavern, ‘Temple’ defined by its stalactite and stalagmite formations all but lost with history to what is now an astonishing underwater chamber. Students lead the dive itself practicing appropriate reel work and buddy and light techniques all under the direct supervision of our head instructor, James Thornton Allan. The skills are perfected on the second dive within ‘Peters’ Cave; home to a cathedral type chamber that divers can surface in floating through narrow corridors.

Day 3 completes the skills required for certification as a cavern diver, of which we will not mention (we cant ruin the surprise!), with Day 4 allowing for adventure dives at new sites within the park, providing the perfect situation for newly qualified divers to utilise there new found skills in the true nature and reason of why cave and technical diving evolved to what it is today…Exploration!

Big Blue Tech’s August Expedition consisted of two students: English technical dive-master intern Andy Holdoway and instructor Panagiotis Iosifoglou of Greek German decent. Past students Sonia Scott and Yvonne Fries returned for a third and second time respectively for the love of the sport, adding further cavern dives to there log. As Andy and Panagiotis were already TDI Advance Nitrox Certified they were qualified to dive on a technical twin set rig, an addition they both agreed lent itself perfectly to the type of diving involved, while the girls utilised recreational kit with bail out pony cylinders across there torso.

Andy found the whole experience exhilarating stating “I feel alive again” with Panagiotis or ‘Panos’ as we call him, remaining speechless for the majority of the trip, every now and again doing the old “This is Sparta” routine before donning his tech kit. The girls loved the trip, as did we all here at Big Blue Tech, and the logistics and planning are already under way for our September Expedition.

If you are interested in our Khao Sok Cavern Expeditions or any of our training courses, please do not hesitate to contact us at

All photographs are © Christos Kardana / Big Blue Tech.


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