Open Circuit
Open Circuit Technical Diving Courses
From your first mixed-gas certification to Advanced Trimix at 100 metres, taught one-to-one and in small groups in Indonesia and Egypt.
Open circuit technical diving extends your range far beyond recreational limits, using enriched air, accelerated decompression and helium-based trimix to dive deeper, longer and more safely.
At Black Water Tek we teach the full TDI open circuit pathway, from the TDI Nitrox Diver course through Advanced Nitrox, Decompression Procedures, Extended Range and the Trimix series up to Advanced Trimix at 100 metres. Courses are taught one-to-one or in small groups on the deep walls of Gili Trawangan, Indonesia, and at the Blue Hole and Canyon in Dahab, Egypt.
Before each course you complete some self-study, either with a manual and knowledge reviews or e-learning. Theory, classroom and equipment sessions always come before any in-water training, and we add extra dives and flexible pacing so you build genuine skill and confidence, not just a card.
The Courses
Choose your open circuit course
TDI Nitrox Diver
Your first step into mixed gas diving. Dive longer and safer on enriched air up to 40% oxygen.
Find out more →TDI Intro to Tech
Formal twin-tank training and your introduction to the technical diving mindset, equipment and skills.
Find out more →TDI Sidemount Diver
Learn to dive streamlined sidemounted cylinders, the configuration favoured by cave and wreck divers.
Find out more →TDI Advanced Nitrox Diver
Dive enriched air from EAN-21 through to 100% oxygen to 40 metres, the gateway to technical diving.
Find out more →TDI Decompression Procedures Diver
Your first staged decompression certification, planning and conducting deco dives to 45 metres.
Find out more →TDI Advanced Nitrox & Decompression Procedures
The most popular technical certification, combining two courses to accelerate decompression to 45 metres.
Find out more →TDI Extended Range Diver
Deep air diving with staged decompression to 55 metres, building advanced rescue and self-rescue skills.
Find out more →TDI Trimix Diver
Use helium-based breathing gases for staged decompression dives to 60 metres, without the effects of narcosis.
Find out more →TDI Trimix Plus Diver
An extended Trimix certification to 75 metres with five dives and a deeper helium range.
Find out more →TDI Advanced Trimix Diver
TDI's most challenging open circuit course, certifying helium-based decompression dives to 100 metres.
Find out more →Not sure which course is right for you?
Tell us your experience and goals and we will map out the right pathway for you.