The TDI Advanced Trimix course provides the training required to competently and safely utilize breathing gases containing helium for dives that require staged decompression, utilizing nitrox and / or oxygen (O2) mixtures during decompression to a maximum depth of 100 metres / 330 feet. The objective of this course is to train divers in the benefits, hazards and proper procedures of utilizing custom oxygen / helium / nitrogen mixtures as breathing gases.

Student Prerequisites
1. Minimum age 18
2. Minimum certification TDI Extended Range Diver or Entry Level Trimix Diver, or equivalent
3. Provide proof of a minimum 100 logged dives with 25 deeper than 30 metres / 100 feet
4. Provide proof of prior logged experience w/ double cylinders and any other unfamiliar equipment such as dry suit

Course Structure and Duration
Open Water Execution
1. Four dives with a minimum accumulated bottom time of 100 minutes
2. At least 2 dives should be deeper than 70 metres

Qualifications of Graduates
Upon successful completion of this course, graduates may engage in technical diving activities utilizing custom trimix mixtures without direct supervision provided:
1. The diving activities approximate those of training
2. The area of activities approximates those of training
3. Environmental conditions approximate those of training