Trimix Rebreather Training to 60 Metres
Take your technical diving beyond recreational limits with professional TDI Mixed Gas CCR training in Thailand. Learn advanced trimix decompression diving procedures, trimix planning and real world CCR technical diving skills to 60 metres.
TDI MOD 2 Mixed Gas CCR Diver Course
The TDI MOD 2 Mixed Gas CCR Diver Course in Phuket, Thailand is the next major progression step for experienced rebreather divers looking to extend their technical diving capabilities beyond Helitrox limits.
This advanced technical diving course teaches divers how to safely plan and execute staged decompression dives using normoxic trimix gas diluent on a closed circuit rebreather (CCR) to a maximum depth of 60 metres (200 feet).
Using trimix diluent reduces narcosis, improves clarity at depth and allows divers to safely conduct deeper decompression dives while benefiting from the efficiency and extended bottom times that CCR systems provide.
What Is the TDI MOD 2 Mixed Gas CCR Course?
The TDI Mixed Gas CCR Diver course is an intermediate-to-advanced rebreather certification program designed for divers who want to safely conduct deeper decompression dives using helium-based diluent mixtures.
The course focuses on:
- advanced decompression procedures
- mixed gas planning
- helium physiology
- emergency management
- bailout strategies
- and technical CCR dive execution
Successful graduates may independently conduct decompression dives using trimix diluent to a maximum depth of 60 metres within certification limits.
Why Use Mixed Gas on CCR?
As divers progress deeper, nitrogen narcosis and gas density become increasingly important operational considerations.
Adding helium to the breathing mixture significantly improves diver performance and safety during deep technical dives.
Benefits of mixed gas CCR diving include:
- Reduced narcosis
- Improved mental clarity at depth
- Lower gas density
- Reduced breathing resistance
- Enhanced decompression efficiency
- Longer bottom times
- Greater operational safety margins
- Improved technical task management
Mixed gas CCR systems are widely used for:
- deep wreck diving
- cave exploration
- scientific diving
- expedition-level technical diving worldwide
What You Will Learn
During the TDI MOD2 Mixed Gas CCR course, divers develop both theoretical knowledge and advanced practical diving skills.
Core topics include:
- Mixed gas decompression planning
- Helium gas management
- CCR system configuration
- Bailout calculations
- Emergency procedures
- Dive execution strategies
- Decompression software usage
- Oxygen toxicity management
- CNS tracking
- Surface marker buoy deployment
- Team communication procedures
- Off-board gas management
- Advanced buoyancy and trim control
- Loop volume management
- CCR failure management
Mixed Gas & Helium Training
A major focus of the course is understanding the operational and physiological effects of helium in technical diving.
Topics include:
- Helium absorption and elimination
- Gas density considerations
- Narcosis management
- Hypoxia awareness
- High Pressure Nervous Syndrome (HPNS)
- Thermal considerations with helium
- Bailout gas optimisation
- Advanced decompression procedures
- Gas switching strategies
- Trimix planning concepts
Students also learn how helium impacts:
- respiration
- thermal insulation
- decompression efficiency
- diver workload
- Maximum Depth & Gas Limits
Students may utilise mixed gas diluent containing a minimum of 16% oxygen, helium-based trimix configurations and appropriate decompression gases including oxygen-rich decompression mixes.
Maximum training depth: 60 metres / 200 feet
Course Prerequisites
To enrol in the TDI MOD 2 Mixed Gas CCR Diver Course, students must:
- Minimum age 18
- Hold TDI Air Diluent Deco CCR or Helitrox CCR certification, or equivalent
- Have a verified log of minimum 50 CCR dives and 50 hours on the unit
- A significant portion of dives must be deeper than 20 metres
- Demonstrate appropriate technical diving competency
Some crossover pathways may allow reduced hours on the unit when transitioning from another TDI-recognised CCR platform.
Course Structure & Duration
Minimum 5–6 Days
Training includes classroom theory, equipment workshops, confined water skill development and multiple open water mixed gas decompression dives.
Typical structure:
- Day 1 Theory & equipment workshops
- Day 2 Confined water drills & bailout procedures
- Day 3–6 Mixed gas open water decompression dives
Students complete:
- minimum six CCR dives,
- minimum 360 minutes underwater runtime,
- progressive decompression dives and multiple deep mixed gas dives.
Phuket provides ideal conditions for advanced mixed gas CCR training.
Benefits include:
- warm tropical water
- deep offshore dive sites
- technical wreck environments
- blue-water decompression opportunities
- professional technical diving infrastructure
Divers benefit from real-world boat diving conditions while developing operational trimix CCR experience.
Normoxic trimix Vs hypoxic trimix
Normoxic trimix and hypoxic trimix are both helium-based breathing gases used in technical diving to reduce nitrogen narcosis and improve diver performance at depth, but they differ primarily in oxygen content and intended operating depth. Normoxic trimix contains enough oxygen (typically 18% or higher) to be safely breathed at the surface, making it suitable for dives generally between 45–60 metres where reduced narcosis is desired without requiring special travel gas procedures. TDI MOD2 Mixed gas course is a normoxic course.
Hypoxic trimix contains a lower oxygen percentage (below 18%), making it unsafe to breathe at the surface due to the risk of hypoxia, and is therefore used for deeper dives beyond approximately 60 metres where helium must replace more nitrogen and oxygen to safely manage gas density, oxygen toxicity and narcosis. Because hypoxic trimix cannot support consciousness at shallow depths, divers must use travel gases during descent and ascent before switching to the deeper hypoxic mix.
Continuing Education After MOD2
After successful completion, divers may continue progressing toward:
- TDI Advanced Mixed Gas CCR Diver (Hypoxic Trimix)
- Deep Exploration Diving
- Cave CCR Training
- Expedition Wreck Diving
- Advanced Technical Exploration
Why Train Mixed Gas CCR in Thailand?
Thailand has become one of Southeast Asia’s leading technical diving destinations.
Advantages include:
- Warm water year-round
- Lower operational costs
- Access to deep dive sites
- Professional technical diving support
- Strong technical diving community
- Internationally experienced instructors
- Excellent travel accessibility
Compared with Europe or North America, Phuket provides exceptional value for advanced CCR education.
Why Choose Tech Dive Asia?
Tech Dive Asia specialises in advanced technical diving and rebreather training.
Unlike recreational centres offering occasional technical courses, our programs focus entirely on:
- procedural precision
- technical diver development
- exploration-level skills
- real-world CCR diving competency
What Makes Our Training Different?
Experienced CCR Instructors. Our instructors actively dive mixed gas CCR systems in wreck, decompression and exploration environments.
Small Team Training. Low student-to-instructor ratios provide safer, more personalised technical education.
Real Technical Diving Procedures. Training reflects actual mixed gas CCR operational procedures used in advanced technical diving.
Progressive Technical Development. Courses focus on situational awareness, bailout management, precision buoyancy and failure resolution.
Unit-Specific Training. All courses are completed on the exact rebreather platform divers intend to use after certification.
👉 Find out more about the team of Instructors and Instructor Trainers at Tech Dive Asia
Begin Your Mixed Gas CCR Training
Train with Tech Dive Asia and develop the advanced skills required for deep helium-based CCR decompression diving in Phuket, Thailand.
Whether your goal is deep wreck diving, exploration projects or advanced technical progression, the TDI MOD 2 Mixed Gas CCR Diver Course is the next major step toward expedition-level rebreather diving.
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