top of page



The TDI Cavern Diver program lays the fundaments of diving in overhead environment. Most basic principles will be taught here it is probably the most important of the cave diving cursus. Students will learn how to “lay line” properly, while maintaining solid fundamental skills and general awareness. In a word, you’ll learn how to multi-task. This is a very challenging course when taken seriously, and we, at CDT Mexico, very much do so…



We will start to venture away from the open water and swim under a natural, hard ceiling, that impeaches direct vertical ascent. Students will learn new aspects such as placement (according to team, line and surrounding environment), positioning and light communication. We will raise dramatically all levels of awareness and learn decision making and how to handle task-loading.

Students will learn how to plan simple overhead dives, considering:
- the use of the rule of 1/6
- the principles of full redundancy and self-sufficiency
- team’s dynamic and communication
- laying a continuous guideline to the surface and potentially connect to a permanent guideline
- emergency procedures and protocols fitting the overhead environment

SUBJECT AREAS (non exhaustive)

During our TDI Cavern Diver Course, we will focus on the following aspect (on top of reviewing everything else from previous levels) Underwater: - refining fundamentals skills - laying a continuous guideline to the surface as a team - team’s light and sign communication - advanced and modified propulsion techniques - touch contact communication in low visibility - problem solving in overhead environment (leakages, mask and light failures, etc) - lost line procedure for the cavern environment - team’s separation procedure for the cavern environment On land: Land-drills and simulations of procedures - laying line and connecting to a permanent guideline - lost guideline - lost diver / team’s separation Briefings and de-briefings - pretty much everything… White board presentations and discussions - rule of 1/6 and conservatism - the cavern zone - specific hazards of the overhead environment - cavern diving etiquette - caves’ bottoms and ceilings - silt outs - specific dangers and consideration - psychological and physiological considerations - mind-control and stress recognition and management - impact and cave conservation


Cavern divers will swim away from the comfort of the open water under hard ceiling and potential hazards proper to cave and cavern environment. Direct and vertical ascent to the surface is now impossible and we must learn how to solve problems on the spot, or alternatively how to “isolate” it and take it safely back to the surface. This is a new way of thinking for open water divers usually performing no-stop dives. This means that divers must develop a high level of awareness in all field. Preparedness and mind-control become paramount in this kind of diving, and students will have to show a conservative mindset as much for their own safety as for protecting the integrity of the fragile cave / cavern environments. Cavern divers will lay line from the open water into the cavern area. Cave ceilings and bottoms are often covered with thin sediment that can lower visibility very quickly. Refined propulsion techniques and close to perfect buoyancy control and trim are now paramount to avoid silt-outs and disorientation. Divers at that level must know their equipment and it’s configuration to a much higher level as previously, in order to solve problems quickly and rationally, without losing any of the fundamental skills such as buoyancy, trim, position and orientation. Therefore, the training at basic level (Sidemount or Intro to Tech) must be of high level and of quality. As divers swim away from the open water, the psychological aspects are of much higher importance. Knowing one-self, couple with healthy non-egoic motivations and high level of preparedness are extremely important mind-skills and character traits of a good and safe Cavern diver. The TDI Cavern Diver course provides you with simple, efficient protocols and helps you develop clear mindset coupled with sound judgement in stressful situations.


Students must be 18 years old, and - certified as a TDI Intro to Tech diver (or equivalent or proven experience), if training in a backmount configuration - certified as a TDI Sidemount diver (or equivalent or proven experience), if training in a sidemount configuration - certified as a TDI Nitrox diver (or equivalent), as we use Nitrox32 as a standard breathing gas - certified as a TDI Cavern diver (or equivalent) - have a minimum of 50 logged dives

DURATION (and the meaning of "performance based training")

The TDI Cavern Diver Course has a duration of 3 days (and a minimum of 4 cave dives), if combined with the TDI Sidemount or Intro to Tech course with CDT Mexico directly, and immediately after. An additional day of training for reviews and checks is required for students coming from another instructors/area and who wishes to continue their training with CDT Mexico. In this case the minimal duration is 4 days. The duration of the course, and the number of dives necessary are performance based. We train until you're adequately prepared to plan and dive in an autonomous manner with a teammate without supervision. Merely performing skills is not enough. Students must show an overall high level of mastery in the following fields: - fundamental skills (breathing, buoyancy control, trim, propulsion) - dive planning (maps readings, orientation and route, gas needs & limitations, cave conservatism) - awareness (self, global and situational awareness) - team’s dynamics (active & passive communication, positioning, pacing & placing) - mindset (positive non-egoic motivation, cave conservatism, cave etiquette, risk assessment) - stress recognition & management (capacity of acting rationally under stress) The evaluation of this qualities of course is quite relative and reflects the perception of the instructor. CDT Mexico instructors are very experienced and specialized in teaching cave divers. We are caring and conscious of the efforts provided by our students during this demanding course(-s). Surely we put the bar quite high, but we also help and direct you to reach it in the shortest possible time, always keeping the quality and the safety at the centre of our attention. “Train Hard – Dive Easy”

WHAT'S YOUR PATH ? - combined courses

If you are a Sidemount and/or Intro to Tech diver from a recognized agency: TDI Cavern + 1 check/review day = 4 days - $1,200 USD If you start from scratch, and wish to train in Backmount configuration: TDI Intro to Tech + TDI Cavern = 5 days - $1,500 USD If you start from scratch, and wish to train in Sidemount configuration: TDI Sidemount + TDI Cavern = 6 days - $1,800 USD


Technical diving courses are charged per day of training, since the courses are performance based and additional days of training are sometimes necessary. The training fee is $300 USD per day / per person. (If two divers are taking the course, the daily fee is $540 USD and $720 for three students.)


The daily fee includes transportation to the dive site and back. Obviously, the teaching, the use of properly rigged cylinders (80cu / 11lt alu) either for sidemount or backmount configurations, with EAN32 as a standard gas, weights and some parts of the equipment if necessary. Also, we always have enough fresh drinking water, O2 kit, complete toolbox and spare parts. The daily fee doesn’t include the basic equipment (wetsuit/dry-suit, fins, masks, computer, etc) nor the entrance fees to cenote parks nor your food, nor the TDI e-learning codes.


Students need to complete the TDI e-learning before the start of the course (unless previously done). Codes are paid in advance together with a down payment of 1 day of training (non-refundable) for the final booking.


Preparing for a technical and/or cave diving course is essential to a successful experience. Before enrolling, fundamental skills must be mastered and knowledge from previous levels is expected. In practice, what does that mean? Students must be able to control their position and remain static in the 3 dimensions, through - controlled, slow and conscious breathing techniques - buoyancy control using the wing/dry-suit with minimal use of lungs for micro-adjustment - trimming body position, gear and configuration - use of advanced propulsion techniques such as modified frog-kick, back-kick, and helicopter-turn - self, global and situational awareness. Additionally, participants should ensure that their equipment is well maintained/prepared and that they are familiar with it. We send you the gear list for your course on demand or you can simply download it yourself here. Most TDI courses have an e-learning, and it is a pre-requisite for us. We’ll require a digital copy of it if previously done, or we will send a TDI e-learning code to you, attached to CDT Mexico directly with several benefits.

bottom of page