🀿 Technical Scuba Diving: Equipment, Courses & Associations

First, a definition. A ‘technical dive’ is a self-contained untethered dive in which the diver switches a breathing gas during the dive. It usually involves the diver in using a “bottom mix” followed by one or two intermediate decompression mixes of enriched air and oxygen. Whenever the diver does not have a direct ascent option to the surface, the dive becomes inherently more dangerous. These types of dives are typically beyond the no-stop time limits of air or enriched air diving tables; they may involve overhead environments such as wrecks, caves, or use of a rebreather. NAUI defines a category of recreational technical diving for purposes of diving instruction and insurance as diving that is not commercial and that meets any of the following conditions: Depths beyond 130 fsw (40 msw), enriched air mixtures with oxygen fractions greater than 41%, or any other non-air mix (trimix), or planned decompression.

So, you know how to scuba dive. You’ve been travelling around, enjoying diving adventures for a few years, and you’ve loved it. But have you ever felt like you want to know more about the equipment that’s allowing you these pleasures? Have you ever wanted to push yourself: to swim further into that cave system, dive down to that wreck, or clamber down that coral wall? If so, then technical diving is for you – it allows you to push yourself further while knowing yourself to be safe because of you enhanced knowledge of your equipment.

Technical diving courses include a professional study into breathing equipment, mixed gases and all other technical aspects of the sport. The guiding light of the technical diving world is TDI (Technical Diving International), which was founded in 1994. Thanks largely to TDI technical diving has evolved into a significant part of the recreational diving business; sometimes even described as the saviour of the scuba industry. Because of the enhanced need for specialist equ ipment manufacturers find “high tech” diving to be a major cash cow. However, technical diving is more than just equipment; it requires a high level of training, personal discipline and dedication.

As technical diving is now ten years old, opportunities for training are more plentiful as other diving associations are catching up with the fashion. But technical diving should not be embarked upon because of trend or caprice – it’s a serious sport which can be dangerous, and only when you have mastered the training can you reap the rewards. That said, Technical diving has enjoyed a good safety record, and is statistically ‘safer’ than non-technical diving. However, technical diving involves more risk on the part of the participants, so any accidents are usually subject to a good deal of scrutiny. There is also a greater potential for accidents during training than in non-technical diving.

Cost is the major drawback in technical diving. As well as the cost of owning a long list of specialized equipment, chartered trips will cost more because of the amount of room a technical diver needs – his kit means that he takes at least twice as much room as a non-technical diver i.e. 2 spaces on a boat. But if the extra costs don’t bother you, there is certainly nothing more thrilling than diving with the expertise and skill of a technical diver.

Technical diving requires specific equipment. The following list covers a general description of the gear a technical student candidate must arrive with for training, typical of the requirements of TDI.


Due to the serious nature of technical diving the prospective technical diver is expected to own his/her own equipment. Part of the discipline of the sport is care and maintenance of equipment, and in ownership of his equipment a technical diver is completely liable for any accidents or failures of his gear.

  1. Backplate & Harness With the system also include 2 sets (4 total) shoulder harness pads and 2 waist band pouches.
  2. Single Bladder Wing 55-65 lbs. lift preferred. LP inflator hose should reach chest level when suited up.
  3. D-Rings — harness is to have 3 D-rings — one on each shoulder and one on the left side side of the waist band. Waist band rings can be either standard rings or fixed position Billy Rings (Abyss, OMS, Highland, or you can make them. The crotch strap is to have 2 d-rings, one in the front, one in the back.
  4. Class-A regulators (2) one with 5-7′ hose and standard low pressure inflator hose (for right hand outlet) the other with low pressure inflator hose and brass SPG. All primary regulators are to be fitted with 300 bar DIN connections.
  5. Stage regulators (2) prepared for oxygen service fitted with a 6″ to 7″ HP hose with metal SPG, these are for decompression cylinders.
  6. Regulator hose should be 44 inches.
  7. Bottom Timer (2) (1 if using computer) electronic bottom timer / depth gauge.
  8. Dive Computer (1) (2 recommended) decompression computers capable of at least 1 Nitrox mixture with a minimum capability of a 60 foot deco stop, download capability or a good multi gas unit.
  9. Compass for navigation.
  10. Back-up lights (2) 3 C-cell size works well.
  11. Primary light (cylindrical canister light with “Goodman Handle” preferred. maximum 50 watts with up to 90 minute burn time recommended.
  12. Wreck Reel 250′ of line, (Aqua Explorers RA8, OMS, EE, AUL, Dive Rite, Reef Scuba etc.)
  13. Safety Reel 130′ to 150′ of line.
  14. A small, very sharp Knife.
  15. 2x Lift Bags or a Surface Marker Buoy and 1 50 lbs. lift bag.
  16. Survival Sausage – inflatable 1 meter size – orange, yellow, lime green.
  17. 2x Small Slates.
  18. Personal Gear – Mask, Fins, snorkel (for rescue simulations).
  19. Exposure suit – a Dry Suit is required for all trimix dives and all dives where average water temp is 75 or less.
  20. For water warmer than 75f a wet suit may be used.
  21. Gloves depending on the environment you’re diving in.

Safety Items

  • Sky Blazer Diver’s Flare kit
  • Whistle or Dive Alert
  • Small signal mirror
  • Jon-line 2 (used for decompression) 1 primary 1 back up – 6-9 feet long
  • Weight belt – metal buckle (4 weight keepers)


  • Back Tanks
  • Divers will be required to have two (2) complete sets for each day of training dives
  • Decompression (stage) tanks.
  • Technical students need 3 cylinders. Two for nitrox, one for oxygen.

Spare Parts/Tool Kit

  • This would include any special regulator plugs, o-rings, replacement batteries, mask straps, fin straps, zip ties, etc.
  • Bungee Cord: you will need a minimum of 20 feet of 3/8 inch diameter bungee.
  • Snap Clips have a variety of snap clips with you for stage bottle rigging, clipping regulators, etc.

Books & Software

All courses at TDI include text for that specific course

Technical Courses

Here is an overview of the technical diving courses offered by TDI


This is the entry level certification course for recreational divers wishing to utilize enriched air nitrox (EAN) as a breathing gas. The objective of this course is to train divers in the benefits, hazards and proper procedures for using nitrox mixes from 22% to 40% oxygen content.

Advanced Nitrox

This course examines the use of EAN 21 through 100% (oxygen) for optimal mixes to a depth of 130fsw/40msw. The object of this course is to train divers in the benefits, hazards and proper procedures for utilizing EAN 21 through 100% (oxygen) for dives not requiring staged decompression. (Decompression techniques may be combined with this course at the discretion of the instructor).

Advanced Wreck

This course provides the training and experience to competently conduct advanced wreck dives, penetration skills and techniques are covered.

Decompression Procedures

This course examines the theory, methods and procedures of planned stage decompression diving. The objective of this course is to train divers how to plan and conduct a standard staged decompression dive not exceeding a maxium depth of 150fsw/45msw unless taught in conjuction with advanced nitrox, Extended Range or Advanced Wreck Courses. The most common equipment requirments, gear set-ups, decompression techniques and decompression mixtures (including oxygen and nitrox) are presented.

Extended Range

This course provides the training and experience required to competently utilize air for dives up to 180 fsw/55msw that require staged decompression, utilizing nitrox mixtures and oxygen during decompression.

Entry Level Trimix

This course provides the training required to competently and safely utilize breathing gasses containing helium for dives that require staged decompression, utilizing nitrox and/or oxygen mixtures during decompression to a maximum depth of 200fsw/60msw.

Advanced Level Trimix

This course provides the training required to competently and safely utilize breathing gasses containing helium for dives that require staged decompression, utilizing nitrox and/or oxygen mixtures during decompression to a maximum depth of 300fsw/100msw.

Rebreather Training

This is the entry-level certification course for recreational divers wishing to utilize a nitrox semiclosed circuit rebreather (benefits, hazards and proper procedures are comprehensively taught).

Nitrox Gas Blender

The objective of this course is to train candidates in the proper technique equipment requirements and hazards involved in blending nitrox gases for recreational scuba.

Advanced Gas Blender

The objective of this course is to train candidates in the proper procedures needed for the preparation and blending of high quality gasses.

Service Technician

This course enables the successful candidate to engage in the preparation of scuba equipment for technical diving gasses.

Overhead Environment/Cavern

This course is designed to develop the minimum skills and knowledge for cavern and overhead environment diving within the limits of light penetration; in addition outlines specific hazards associated with cave diving. The cavern course is not intended to provide instruction for cave diving environments.

Introductory Cave

This course is an introduction to the basic principles of cave diving utilizing a single cylinder. Introductory cave diving is the second level in the development of safe techniques for cave diving, directly building upon the cavern course.


This course is the third stage of training in the series of TDI’s cave diver development program. Advanced cave dive planning the practical execution of different types of cave systems and scenarios divers encounter are presented.

Technical Divemaster

This course is the third stage of training in the series of TDI’s programme.

Technical Diving Associations