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TDI TRIMIX DIVER Extend your capabilities with multiple deco gases and depths to 60m....

TDI Trimix Diver with Tech Asia

The TDI Trimix course provides a safer means for deep water exploration, as deep as 60m/200ft, There is a strong emphasis on safety and skill development, since at these depths, any small problems that may occur need to be solved correctly, and much faster than you will find is necessary at 40m/130ft or shallower. Experience, familiarity with procedures and equipment, and comfort, are the key to having fun and diving safely. The course certifies divers to use normoxic trimixes (meaning the gas can safely be breathed at the surface), and two decompression gases are normally carried at this level of diving.

This training is an alternative to TDI Extended Range Diver, which is of a similar level but is air based. You don't have to do both courses, just one or the other. It is prerequisite to the TDI Advanced Trimix course.  TDI eLearning is available - please contact us for details.

What will TDI Trimix certification allow you to do?

So now you can hold a certification to 60m/200ft. What does this offer? This diving range opens the door to many new dives sites, and while deep, is still a depth range that still allows a good balance of bottom time, easily up to half an hour, without decompression becoming too long.

In Puerto Galera itself this course will get you to some of the most beautiful and atmospheric places on our outer reef. Sweetlips Corner, Markus Cave, The Fishbowl, and the awe inspiring Secret Reef, or Blackfish Pinnacle on Verde Island. Check out our Dive Sites map for more. Interested in wreck diving? Consider that ships rarely sink in shallow water, nor last long if they do. For the Trimix Diver an example of a "must see" is the WWII British aircraft carrier HMS Hermes, sunk off Eastern Sri Lanka at just over 50m. Our trips there have provided some of our finest dives. At this level, your possibilities are endless!


  • Must be at least 18 years of age. 
  • Must be at least a TDI Advanced Nitrox & Decompression Procedures Diver or equivalent. 
  • Proof of 100 logged dives.

Program Content and Limits

  • Confined waterwork will be completed dealing with equipment set-up, handling and dive technique, plus emergency skills and stress management exercises.
  • Four decompression dives, at least two of which are below 40m/130ft, and not deeper than 60m/200ft.
  • At least 100 minutes of open water bottom time.
  • Bottom PO2 limited to a maximum of 1.4 ATA, decompression gas PO2 will not exceed 1.6ATA.
  • All bottom gases will be non-hypoxic, having not less than 18% oxygen.

What You Will Learn

In the TDI Trimix Diver course you will expand on what you learned during Advanced Nitrox & Deco Procedures. Dive planning becomes more involved due to depth and loss of gas scenarios that need to be considered, and exposures are higher. Further fine tuning of equipment may be required to make sure it is really helping you in the water. During the classwork, land drills and in water you will learn about : 

  • Equipment configuration and Dive Technique.
  • Advanced Dive Planning and Gas Matching.
  • Risk analysis.
  • Respiratory physiology.
  • Understanding Helium, Oxygen, Narcosis, CO2 effects etc.
  • Decompression theory and DCI avoidance and management.

Note: As with other TDI programs, the diver must complete and pass the written examination, complete all open water requirements efficiently and safely, and demonstrate mature and sound judgement in dive planning and execution in order to be certified.

Equipment, Materials, What's included?

You will find details of what is included and not included across all TDI courses on the Overview page.

The TDI Trimix course is normally taught in double tanks although Sidemount is an option for those already certified. Two decompression tanks are generally used. Either a printed manual, or eLearning, are available for this course.

Course Options

In the TDI progression the diver has a  choice of taking either Extended Range Diver or Trimix Diver. Being air based, Extended Range is depth limited at 54m/180ft and is an overall less well rounded certification for deep diving. However if you prefer it, time taken is the same. During the Trimix course you can expect a helium cost of roughly $250-300/Php12,000-15,000, not applicable in Extended Range.