Technical training

Decompression Procedures

Planning and executing dives with a mandatory decompression obligation.

Recreational dives are generally planned to allow direct ascent without mandatory staged decompression. Technical decompression intentionally creates an obligation.

That changes the emergency model completely. Gas planning becomes critical because direct ascent may no longer be the planned response to every problem — the diver must have enough gas to complete the decompression regardless of what goes wrong.

The course covers decompression theory, planning software and tables, staged ascents with gas switches, and the contingency planning that makes the obligation manageable.

Northern Territory wreck diving, represented by an AI-generated editorial image.

Track	Technical
Prerequisites	Advanced Nitrox typically required; Good buoyancy and trim; Redundant equipment configuration
Agency equivalents	TDI: Decompression Procedures · PADI: Tec 45/50 · IANTD: Technical Diver · RAID: Deco 50

What it teaches

decompression theory and algorithm behaviour
planning staged decompression with software and tables
gas requirements including contingency reserves
staged ascents and stop discipline
managing a lost decompression gas
equipment redundancy and failure analysis

The emergency model changes

In recreational diving, the answer to almost any problem is to end the dive and ascend. Once a decompression obligation exists, that option is gone.

Every failure has to be resolvable at depth or during a controlled ascent, which is why redundancy in gas, buoyancy and instrumentation stops being optional.

Buoyancy stops being cosmetic

Holding a stop at 6 metres for twenty minutes in swell, with a stage cylinder and changing buoyancy as gas is consumed, is a genuine skill.

Poor buoyancy becomes increasingly consequential when mandatory decompression or overhead environments are involved — which is why technical training front-loads trim and control work.

Where this qualification matters in Australia

Sites where holding this certification genuinely changes what you can do — not a list of everywhere it is accepted.

Ships' GraveyardNumerous vessels deliberately scuttled outside Port Phillip Bay across a wide depth range.Port Phillip Heads WallsWalls starting at 12 metres and continuing beyond 90 — the terrain behind Victoria's technical culture.SS NordA steamer lost in 1915, lying around 42 metres off the Tasman Peninsula.Piccaninnie PondsA karst spring of extraordinary clarity, with the Cathedral chamber and a chasm beyond 100 metres.Lonsdale WallVictoria's signature wall — sponge-covered, vertical, and continuing well past recreational depth.

Natural next steps

Courses that build directly on this one.

Trimix DiverAdding helium to manage narcosis, oxygen exposure and gas density at depth.Closed Circuit Rebreather DiverRecycling breathing gas to extend duration, reduce bubbles and optimise oxygen exposure.Cave DiverFull overhead penetration diving, where direct ascent is not available at any point.

Courses that lead here

Deep DiverExtending recreational limits to 40 metres, with the gas planning and narcosis awareness that requires.Wreck DiverDiving wrecks safely, and understanding where external touring ends and penetration begins.Sidemount DiverCarrying cylinders at your sides — redundancy, streamlining and access through restrictions.Advanced NitroxHigh-oxygen decompression gases and oxygen-clean equipment — not ordinary recreational Nitrox.

Agency versions of this course

The same qualification under different names. All are mutually recognised by operators.

TDITaught as “Decompression Procedures”.PADITaught as “Tec 45/50”.IANTDTaught as “Technical Diver”.RAIDTaught as “Deco 50”.

Centres documented as offering this level of training

Businesses where the relevant capability is verified or advertised. Always confirm the specific course directly.

Dive Dive DiveA long-standing Brisbane business associated with technical training alongside recreational courses, retail and servicing. Technical capability should be audited service by service rather than assumed.Dive Centre ManlyA Northern Beaches operation with a long-standing presence at Shelly Beach, offering recreational training, boat diving and technical pathways.Frog Dive SydneyA long-established Sydney business associated with recreational and technical training alongside retail and workshop services.Abyss Scuba DivingA Sydney operation associated with training across recreational and technical levels, boat diving and equipment services.Dive Centre BondiAn Eastern Suburbs operation providing recreational training, local diving and technical pathways.Academy of ScubaA Melbourne training business offering recreational courses with technical pathways.Diveline Scuba CentreA Victorian business associated with technical training and gas support alongside recreational courses.AquabilityA Victorian operation associated with technical diving training. Exact agency, course levels and gas support require verification.Bay City ScubaA Victorian business associated with recreational and technical training alongside equipment and gas services.Ocean DiversA Victorian operation associated with recreational and technical training and access to Port Phillip diving.Snorkel & Dive Safari AltonaA Melbourne retail and training business, listed among Victorian operations associated with technical services.All About ScubaA Victorian training operation listed among those associated with technical diving. Capability requires verification.

Frequently asked questions

Is decompression diving dangerous?

It carries risks that recreational diving is specifically designed to avoid. Managed with proper training, redundancy and conservative planning, it is undertaken safely by many divers.

Can my recreational computer handle decompression?

Many modern computers display decompression obligations, but technical diving generally uses computers with technical algorithms, gas switching support and a backup device or tables.