TDI Trimix Diver Course
Train to manage helium-based mixes for deeper, safer technical dives
TDI Trimix Diver Certification in Nanaimo
Extend your depth range, reduce narcosis, and unlock the world of true deep exploration.
The TDI Trimix Diver course is the gateway to deeper, safer technical dives beyond the limits of standard gas mixtures. By incorporating helium, trimix significantly reduces narcosis at depth, allowing divers to remain clear-headed while exploring advanced wrecks, deep walls, and complex environments. Training with Nanaimo Dive Outfitters gives you access to cold-water conditions, real-world trimix scenarios, and experienced technical instructors who guide you step by step into deeper diving.
Who is the Trimix Diver course for?
The TDI Trimix Diver course is designed for technical divers who want to:
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- Extend their operational depth range beyond traditional technical limits
- Reduce narcosis while maintaining clarity and precision during deep dives
- Build the gas-planning, equipment, and procedural skill set needed for serious exploration
- Progress toward advanced technical pathways such as Advanced Trimix, Advanced Wreck, or deep cave programs
Minimum age for participation is 18, and students must already hold TDI Advanced Nitrox and Decompression Procedures certifications or equivalents, along with a minimum of 100 logged dives.
What to expect in your TDI Trimix Diver course
Trimix training is scheduled throughout the year and typically combined with deep sites around Nanaimo, Gabriola, and the surrounding region. Your course includes classroom learning, extensive gas-planning workshops, and multiple open-water training dives conducted on trimix.
A typical schedule includes:
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- Classroom sessions covering trimix theory, gas planning, decompression strategies, and emergency procedures
- Dry-land equipment configuration and stage-cylinder handling
- Instructor-led deep trimix dives with demonstration of skills and problem-solving
- Supervised dives where you plan and execute the full dive profile, including switches and decompression stops
This progression ensures you gain comfort, stability, and confidence while working at depth.
What the TDI Trimix Diver course teaches you
The Trimix Diver course is divided into three main phases.
#1. Knowledge development
You’ll review advanced planning concepts, including:
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- Equivalent narcotic depth (END) strategies and helium balancing
- Oxygen exposure limits (CNS, OTUs), helium isobaric counterdiffusion, and inert gas kinetics
- Gas-planning formulas, volume calculations, and decompression schedule construction
- Equipment considerations such as stage-cylinder rigging, regulator redundancy, and labeling
- Contingency planning for gas loss, equipment failure, or omitted decompression
#2. In-water skill development
During initial dives, you’ll practice:
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- Trim and buoyancy control at depth with multiple cylinders
- Gas-switching protocols and verification procedures
- Managing stage and decompression cylinders efficiently
- Precision navigation, team communication, and situational awareness
- Problem-solving under narcosis-mitigated conditions
- Deployment of SMBs or lift bags for deep-water decompression ascents
#3. Deep open-water trimix dives
You will complete multiple deep dives using custom trimix blends appropriate for the planned depth, typically approaching 60 metres / 200 feet.
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- Trimix Dive 1: Structured descent, gas management, skill demonstration, and controlled ascent
- Trimix Dive 2+: Student-led planning and execution with full adherence to decompression schedules and gas switches
These dives prepare you to use helium mixes independently within the scope of your training.
Gear expectations for the TDI Trimix Diver course
All required technical equipment is available through Nanaimo Dive Outfitters, including:
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- Drysuit and thermal undergarments
- Doubles or sidemount configurations
- Stage and decompression cylinders
- Redundant primary and backup regulators
- Trimix-capable dive computers
- Reels, SMBs, and deep-water signaling equipment
Deep-water training is always completed in a drysuit, as cold temperatures and long decompression times require proper thermal protection.
Advanced skills for confident deep diving
Learning trimix in British Columbia prepares you for deep diving anywhere in the world. Cold water, low visibility, and demanding conditions sharpen your awareness, precision, and planning skills. Warm-water trimix feels straightforward by comparison. Your TDI Trimix Diver certification is recognized internationally and sets the foundation for deeper pathways, including TDI Advanced Trimix, TDI Advanced Wreck, and CCR trimix programs.
What’s included
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- TDI Trimix Diver eLearning
- All required training dives
- Use of stage cylinders and technical equipment
- Small class sizes to ensure focused instruction
- Access to gear rentals for doubles, stages, and regulators
Student perks: Graduates receive discounts on purchases, gas fills, and future specialty courses, plus ongoing access to our local technical diving community.
Coming from out of town?
If you’ve already started your Trimix Diver course elsewhere, we can complete your training through a multi-agency referral. Many divers travel to Nanaimo for deep, cold-water experience that accelerates skill development and confidence. Visiting the island for work or a dive trip? We offer flexible scheduling and access to deep-water sites ideal for trimix profiles. Contact us for availability and custom course planning.
Trimix Diver Course FAQ
Does trimix training help reduce gas narcosis completely or just minimize it?
Trimix minimizes narcosis significantly, but it never eliminates it entirely. Your instructor will teach you how to plan END targets that match the dive’s risk level.
Will I need to buy my own doubles or sidemount system before starting the course?
You can rent gear at NDO, but most divers benefit from training in the configuration they plan to use long-term.
How long are typical trimix dive profiles, including decompression?
It varies, but many training dives exceed an hour due to ascent and decompression obligations.
Do I have to mix my own gases to take this course?
No. You’ll learn how gas blending works, but all training mixes are provided by the shop.
Can trimix be used on shallower dives as well?
Yes. Some divers use “normoxic trimix” on dives in the 150-foot range for clarity and reduced narcosis.
Does the course prepare me for using trimix on wreck or cave dives?
It builds the foundation, but overhead environments require additional specialty training.
Do most divers struggle more with the physics or the gas-planning math?
Both can be challenging, but the gas math usually takes the most repetition to master.
What’s the biggest difference between this course and TDI Advanced Nitrox
This course adds helium-based gas planning, deeper operational limits, and more complex diver management scenarios.
Ready to become a certified diver?
Scuba diving opens the door to new experiences, travel, and friendships. Training with Nanaimo Dive Outfitters gives you confidence in one of the richest cold-water ecosystems in the world.
Start your SDI eLearning today or contact us to reserve your spot in an upcoming class.
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