The TDI Advanced Trimix Diver Course is the pinnacle of technical diving for open circuit divers wishing to extend their depth range to as deep as 100 metres utilizing hypoxic levels of oxygen (below 17 percent). This course is perhaps one of the most informative and challenging of all the TDI open circuit courses and will significantly advance your technical diving education.  Few divers get to this level so you will be a member of an elite divers group.

The Training

  • At home study – once you have signed up for the course, we will provide you with a manual in advance of your practical training to work through at home. You will then go through key areas in greater detail with your instructor and cover areas such as plus many others:
    • Diver physiology and helium absorption 
    • Decompression options
    • Equipment considerations
  • Classroom – After you have reviewed the key knowledge areas and ready to go you will then join your instructor for the practical element of your training and cover the following areas:
    • Gas analysis procedures
    • Buddy rescue drills
    • Dive planning
  • Practical training – After you have covered the key knowledge through the online learning, you will then join your instructor for 4 open water dives where you will cover the following plus much more:
    • Multiple failure management
    • Cylinder switching and isolation
    • Team discipline and dive planning


  • Minimum age 18 years old 
  • The TDI Extended Range or TDI Trimix qualification or equivalent and proof of 100 dives (25 of which must be below 30m)
  • You will need to complete a self-certification medical statement. If you have any medical conditions you think may prevent you from scuba diving please contact us and we will try to be of assistance




  • Reading material + certification
  • Cylinders (gases additional due to changing cost of Helium)
  • 4 Open Water Dives
  • Transport to and from dive sites
  • 10% off Aqualung + APEKS dive accessories

Note: Manual, certification and kit hire is not included

Time commitment 

The TDI Advanced Trimix course takes 4 days. If you have not dived with us before, then we will require you to do an additional check dive with us (charged as per fun diving prices)

Contact us for further details