TDI Trimix Instructor

The TDI Trimix Instructor course provides the training required to competently and safely teach breathing gases containing helium with no less than 18 percent oxygen (O₂) for dives that require staged decompression to a maximum depth of 60m.

Prerequisites DI Trimix Instructor :
  • Min. 21 years old
  • Min. TDI Advanced Nitrox and Decompression Procedures Instructor or equivalent
  • Min. TDI Trimix diver or equivalent
  • Provide proof of 250 logged dives with a minimum of 20 logged Trimix dives outside of training, 10 of these dives must be in the last 12 months
  • Proof of 15 certified advanced nitrox or decompression procedures divers; minimum of 10 must be decompression procedures divers


  • Dives: 4 decompression dives
  • Total bottom time: 100min
  • 2 dives must be deeper than 45m
  • Min. number of classroom and briefing hours is 8

To complete this course,
students must:

  • Satisfactorily complete the TDI 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 TMX Diver course
  • Demonstrate proficiency in teaching the TDI TMX Diver course
  • Present at least 1 graded presentation on a TMX topic