NSS-CDS Training Program

Trimix Cave Diver/CCR Trimix Cave Diver


Diving beyond the safe operating limits of your gas mixture is part of the five Rules of Accident Analysis. It’s why the depth limit for entry-level Cave Diver training is 40 m/130 ft. But what if you have a legitimate need to go deeper? This is where the Trimix Cave Diver course comes in.

On deeper cave dives, using helium-based gas mixtures is essential. There is more to Trimix cave diving, however, than simply taking an open-water Trimix course and trusting it will apply equally to caves. It won’t.

There are aspects of Trimix use which are unique to cave diving. They include the need for more precise dive planning and gas management. Decompressing from a Trimix cave dive may need to begin long before you reach the exit. Are you prepared for this?

Even if you already possess Trimix Diver certification, taking the Trimix Cave Diver course is essential. And, if you are an active cave diver looking to go deeper, this may be the best way to acquire your Trimix training and certification.


  • Be at least 18
  • Be certified to the full Cave Diver or CCR Cave Diver level or equivalent by a widely recognized training organization
  • Have at least 50 non-training-related cave dives past initial Cave Diver certification


  • Typically two days
  • At least three dives

Find an instructor

Course Standards

Form These are the standards instructors must follow when teaching this course. It includes information on student and instructor prerequisites, course content, skill requirements and limits of training.