Learn deep diving with helium, reduce narcosis and improve safety on technical dives.
TDI Trimix Diver Course to 60m
Take the next step into deep technical diving with the TDI Trimix Diver course in Phuket, Thailand. This advanced program trains divers to safely conduct decompression dives using trimix (helium-based gas mixtures) to reduce narcosis, improve clarity, and increase safety at depth.
The TDI Trimix course is the natural progression after Extended Range, opening the door to deeper diving with better control and reduced physiological stress.
What Is the TDI Trimix Diver Course?
The TDI Trimix Diver course teaches divers how to plan and execute dives using helium-based breathing gases.
Trimix combines:
- oxygen (O₂)
- nitrogen (N₂)
- helium (He)
By replacing part of the nitrogen with helium, trimix reduces:
- nitrogen narcosis
- gas density at depth
- work of breathing
This allows divers to operate more safely and clearly at greater depths.
Why Use Trimix Instead of Air?
As depth increases, air becomes increasingly limiting.
Problems with Air at Depth:
- increased narcosis (mental impairment)
- higher gas density (harder to breathe)
- reduced awareness and slower reaction time
- CNS Oxygen toxicity
Benefits of Trimix:
- reduced narcosis → clearer thinking
- lower gas density → easier breathing
- improved safety margins
- better performance at depth
👉 Trimix is essential for serious deep diving.
Extended Range vs Trimix – What’s the Difference?
Understanding this progression is key.
Extended Range:
- diving on air/nitrox
- limited by narcosis
- suitable for moderate depths
Trimix Diving:
- uses helium to reduce narcosis
- allows deeper, safer dives
- improves mental clarity and control
👉 The TDI Trimix course is where divers move from managing depth to controlling it safely.
Why Take Your Trimix Course in Phuket?
Phuket provides ideal conditions for technical diving training:
- warm water for long decompression dives
- access to deeper offshore dive sites
- access to deep inland dive sites
- real-world conditions for technical training
- efficient logistics
This allows divers to gain practical experience in real dive environments.
What You Will Learn
The TDI Trimix course focuses on deep decompression diving using helium-based gases.
Theory Topics Include:
- gas density and work of breathing
- narcosis management
- helium physiology
- advanced decompression planning
- multi-gas dive planning
- oxygen exposure tracking
- risk management and contingencies
Practical Skills Developed
This course significantly increases complexity and responsibility.
Skills Include:
- advanced buoyancy and trim at depth
- multi-gas switching procedures
- decompression stop precision
- emergency and bailout procedures
- team diving and communication
- task management under increased load
Equipment Used During the Course
Divers will use a full technical diving setup:
- twinset or sidemount configuration
- multiple stage/decompression cylinders
- trimix bottom gas
- nitrox and oxygen decompression gases
- multi-gas dive computers
Real Challenges in Trimix Diving
This is where technical diving becomes significantly more demanding.
Divers must manage:
- complex gas planning
- multiple gas switches
- long decompression obligations
- increased task loading
- maintaining awareness at depth
The course is designed to build confidence and precision in these areas.
Who Is This Course For?
The TDI Trimix Diver course is ideal for:
- Extended Range divers progressing deeper
- technical divers seeking improved safety at depth
- wreck and exploration divers
- divers preparing for Advanced Trimix or CCR
Course Prerequisites
To enrol, you must:
- Be at least 18 years old
- Hold TDI Extended Range certification (or equivalent)
- Have appropriate technical diving experience
Course Structure
(Minimum 5–6 Days)
- Day 1: Theory and dive planning
- Day 2: Skills development
- Days 3–6: Open water trimix dives
Each dive increases depth, complexity, and decompression requirements.
What Comes After Trimix?
Completing the TDI Trimix Diver course prepares you for:
- Advanced Trimix
- CCR mixed gas diving
- overhead – cave, wreck, mine diving
- expedition-level technical diving
- deep wreck exploration
Why Choose Us for Your Trimix Course?
- experienced technical diving instructors
- real deep diving environments in Phuket
- small group training
- strong focus on safety and discipline
- clear progression into advanced training
You will leave this course ready to dive deeper with confidence.
Contact Us
Have questions or need help? Use the form to reach out and we will be in touch with you as quickly as possible.