Technical diving explained


3 minute read

What is technical diving? 👌🏻

Technical, or tech, or “tec” diving is a branch of scuba diving that takes you beyond recreational limits of depth, time, location, and gases.

Tec diving begins when there is no direct route to the surface, wether it’s full decompression diving, an overhead environment, or an overstaying of time which prevents you from ascending straight up due to a false ceiling.

There is more risk of hazards during technical diving, which is why we need to train and practise these kinds of diving safely. Developing new skills and experience is paramount when undertaking more complex, technical diving.

Types of technical diving

You can expand your diving knowledge to plan longer dives at shallower depths, do deeper1 dives, learn about decompression procedures, train to penetrate caves and wrecks, and learn the complexities of breathing mixed gases such as nitrox and trimix.

1Recreational depth is generally considered to be up to 40m/130ft

Technical diving can include:

  • Cave/overhead/wreck diving - penetrating overhead environments
  • Twinset/sidemount diving - utilising technical equipment setups
  • Rebreather diving - utilising rebreather systems
  • Decompression “deco” diving - diving to depths/times that require decompression stops - not ascending directly to the surface
  • Mixed gas diving

Technical diving equipment

In most cases special equipment is needed for technical diving, for example, a Sidemount, Twinset, or Rebreather setup.

Sidemount setup

Sidemount is a configuration prevalent in cave diving but is also used for penetrating wrecks. This is because a cylinder can be taken off and pushed through in front of you when space is tight. With sidemount diving, fully-independent single tanks are mounted to your sides, with independent regulators for each.

This configuration can be used by divers that want to dive deeper and longer, and perhaps have back issues and don’t want to be lifting a heavy unit onto their backs.

Sidemount diving in Egypt

Sidemount diving in the Red Sea, Egypt

Twinset setup

The Twinset setup is where two cylinders are back-mounted, usually attached together via a manifold that controls the release of gas. You use a single regulator setup to breathe from with this setup (with a backup, as normal).


A rebreather is a machine that recycles exhaled gas, “scrubbing” the CO2 from your breath, allowing it to run back through the loop to be inhaled again. Oxygen is injected to top up the gas in the loop, and this type of setup can be used for extremely long and decompression dives.

Trying rebreather diving in NDAC, UK

Trying rebreather diving in NDAC, UK

Technical diving courses

Always get appropriate training and dive within your limits.
Don’t attempt any form of technical diving or use technical diving equipment unless qualified or under instruction.

This is not an exhaustive list, only the agencies that I have experience or connections with.

Get ready for some acronyms


RAID - Rebreather Association of International Divers

Sidemount training in NDAC, UK

Sidemount training in NDAC, UK

PADI - Professional Association of Diving Instructors

GUE - Global Underwater Explorers

IANTD - International Association of Nitrox and Technical Divers


Technical diving trips

Getting qualified in a form of technical diving opens up many more opportunities for diving trips:

Scapa flow - Scotland, UK

WWI wrecks in Scotland, UK. A lot of the wrecks are at technical depths (40m/130ft+). Penetrating and diving amongst these wrecks will require some technical training to make the most of your time.

Oban - Scotland, UK

More metal! To spend time at the depths that these wrecks are at may require decompression diving training or using a twinset/sidemount configuration.

Chuuk (Truk) Lagoon - Micronesia

Again, to spend time amongst these wrecks it’s advised that you undertake technical training in order to use one of the aforementioned technical equipment setups.

Cave diving - Tulum, Mexico

To penetrate some of the Mexican caves it’s well worth training on a sidemount system. This gives you more flexibility and more time in the water.


I’ll be expanding on some of these topics in more detail in later articles - sidemount diving (my preferred setup), and decompression diving.

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