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The TDI Sidemount Diver Course teaches students how to use side-mounted primary cylinders as an alternative to back-mount. It is taught in a redundant configuration and focuses on the fundamental skills of technical diving.
The course is a necessary preparation before engaging in a technical or cave diving course in a sidemount configuration.



Side-mount configuration is minimalistic and more streamlined. For advanced sidemount divers, it also provides true gas redundancy, but to fully enjoy it, you need solid basic skills and a clean, streamlined equipment set up.

The TDI Sidemount Diver Course with CDT Mexico focuses on getting students ready for not only sport dives, but for technical training as well. We will have a deep look into this very versatile but more complex configuration, and new specific aspects such as harness, wings and cylinders trimming and positioning, regulator switches in all conditions, including in no visibility and along a line (descent or cave line).

Students will learn how to configure their kits themselves with CDT Mexico and will understand it closely, and not merely dive it.

After exiting our course, divers also are proficient with the fundamental techniques of technical and cave diving, such a close to perfect buoyancy and trim control, breathing control, advanced propulsion techniques including modified frog-kick, reverse kick and helicopter turns.

Gas planning on land and gas management under water are also a new areas of discovery for sport divers as they enter technical diving. We will look at the rule of thirds and the concepts of conservatism as well as awareness of the gas supply and maintaining gas redundancy while underwater.


Finally, you’ll learn sequences and how to be efficient in all areas, such as do/doff sequences and water entry/exit protocols.

SUBJECT AREAS (non exhaustive)

During our TDI Sidemount Diver Course, we will focus on the following aspect (on top of reviewing everything else from previous levels) Underwater: - gas management (awareness, reading and keeping redundancy) - regulator switching techniques (two hands, one hand and in low visibility) - hand and light communication - basic fundamental techniques : breathing, buoyancy, trim, propulsion, and positioning - advanced propulsion techniques : mod frog kick, mod flutter kick, reverse kick and helicopter-turn - problem solving : mask replacement, cylinders rigging failure, bungee failure, etc. - leakage and haemorrhages : valves, regulator first and second stage, free-flow, LPI hose, etc. - lift bag deployment On land: Land-drills and simulations of procedures - configuration and set-up - pre-dive checks and team’s dynamic - do/doff sequences - communication - gas switches simulations Briefings and de-briefings - pretty much everything… White board presentations and discussions - awareness and mind-set - rule of 1/3 and conservatism - keeping gas redundancy and regulator switches - dive planning - potential failures and counter-measures - emergency and safety procedures - psychological and physiological considerations - mind-control and stress recognition and management


Diving sidemount requires a higher level of awareness from the divers, as the complexity of the equipment configuration increases. Divers need to put almost constant attention to the gas supply and correct gas redundancy, regulator switches at proper intervals and the need to readjust the cylinder’s position as their trim changes while the gas depletes. Clearly, it is much more task overloading than most sport divers are accustomed to. Sidemount divers also need a deeper understanding in gas planning, as they carry redundant cylinders and apply new rules and new concepts such as conservative thirds, rock-bottom reserves, gas matching and eventually cylinders matching. It is obviously extremely interesting to learn, and if you’re curious enough, you’ll find addicted to the theory side as well as the diving part ! Well, ok, almost as much !


Students must be 18 years old, and - certified as an SDI Open Water Scuba Diver (or equivalent) - have a minimum of 20 logged dives

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

The TDI Sidemount Diver Course has a duration of 4 days with CDT Mexico. 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 and sidemount 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.


TDI Sidemount diver = 4 days - $1,200USD


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. 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.

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