TDI Technical Diving

TDI Trimix Diver Course

Learn to plan and conduct staged-decompression dives using normoxic trimix to reduce inert-gas narcosis at depth. The course develops precise multi-gas management, decompression planning, contingency procedures and team performance to a maximum of 60 metres.

Start a Conversation

Course at a Glance

Minimum age18 years

ExperienceAdvanced Nitrox, Decompression Procedures and 100 logged dives

Training4 decompression dives; 100 minutes bottom time

Maximum depth60 metres

Who This Course Is For

Advanced Nitrox and Decompression Procedures divers progressing to helium-based open-circuit diving.
Technical divers seeking improved narcosis management for deeper objectives.
Divers building experience toward Advanced Trimix or advanced wreck training.

Prerequisites and Readiness

Minimum age 18.
TDI Advanced Nitrox Diver and TDI Decompression Procedures Diver, or equivalent.
Proof of at least 100 logged dives.
Demonstrated recent experience with the selected technical configuration and decompression procedures.

How Training Works

The course includes four decompression dives with at least 100 minutes of accumulated bottom time. At least two dives are deeper than 40 metres, with controlled progression to a maximum of 60 metres. Bottom mixtures contain at least 18% oxygen and must meet current TDI gas-selection requirements.

Course duration is performance-based. Meeting minimum attendance or dive numbers does not guarantee certification; all required knowledge and skills must be demonstrated consistently.

Skills and Knowledge

Plan trimix dives using oxygen, nitrogen and helium exposure limits.

Calculate gas volumes, reserves, decompression and contingency schedules.

Analyse, label and positively identify multiple breathing gases.

Manage multiple stage or decompression cylinders while maintaining buoyancy and trim.

Respond to simulated gas loss, equipment failure and omitted-decompression scenarios.

Execute team gas switches, DSMB deployment and controlled staged ascents.

Continue Your Development

Technical capability is developed through deliberate practice and experience between formal courses. Your next step should reflect your recent diving, equipment configuration and objectives.

TDI Extended Range CCR Training Explore All Training

The Blue Water Ascent approach

Competence Before Certification

We coach understanding, judgement and repeatable performance—not minimum-standard completion. Training is adapted to the diver while every certification requirement and course limit is preserved.