TDI Advanced Trimix Instructor

The TDI Advanced Trimix Instructor course provides the training required to competently and safely teach breathing gases containing helium for dives that require staged decompression to a maximum depth of 100m. The objective of this course is to train instructors to teach the benefits, hazards and proper procedures of utilizing custom oxygen, helium, and nitrogen mixtures as breathing gases.

Prerequisites TDI Advanced Trimix Instructor :

And meet one of the following experience requirements:

  • Certify at least 10 extended range divers or Trimix divers to depths of at least 45m
  • Assist with at least 2 complete TDI Advanced TMX classes taught by an active TDI Advanced TMX Instructor and provide a letter of recommendation from the assisted instructor(s)


  • Dives: 4 decompression dives
  • Total bottom time: 100min
  • 2 dives must be deeper than 70m
  • Min. number of classroom and briefing hours is 8

To complete this course,
students must:

  • Satisfactorily complete the TDI Advanced TMX course written examination and be able to adequately explain each answer to a prospective student
  • Demonstrate mature, sound judgment concerning training, dive planning and execution
  • Demonstrate proficiency in every skill required in the TDI Advanced TMX Diver course
  • Demonstrate proficiency in teaching the TDI Advanced TMX Diver Program
  • Present at least 1 graded presentation on an Advanced TMX topic