Lesson 1, Topic 1
In Progress



Most isothermal suits are made of neoprene (rubber foam), a material with great insulating power. There are suits with different thicknesses (from 1.5mm to 7mm or more) and can be lined inside and outside with a synthetic fabric, usually nylon or lycra. The inner lining has the function of making them more comfortable to wear and undress, and the outer lining serves to make them more resistant to abrasion.

Neoprene is a foam formed by small cells closed and filled with gas. It is, therefore, a material whose weight is extraordinarily low in relation to volume, which gives it a very high floating power. The greater the thickness of the neoprene, the greater the protection against cold, but consequently, the greater its floating power will also be. This material also undergoes changes in its thickness with the increase and reduction of the depth of the dive (increase in pressure).


There are three types of isothermal diving suits that should be chosen according to the type of diving practice and the temperature conditions of the environment.

  • Wet Suit
  • Semi-Dry Suit
  • Dry Suit


They allow a small amount of water to enter, which is retained between the neoprene and the diver’s skin being rapidly heated. The effectiveness of the fact is all the greater the better the isolation of the body with water.

Therefore, the fact should function as a second skin (fair, but not tight), avoiding the circulation of water inside and not allowing the rapid renewal of the water film heated by the body. This type of suit exists on the market in models for all tastes and types of use.

It can be one-piece or multi-piece, with or without hood, with or without hood, can have or without seals on the wrists and ankles and be made in neoprene with different thicknesses, densities and patterns.

When choosing a wet suit it is necessary to try it. The size is important, can not be small, not to get tight, and should not be large so that no bags of water are formed between the suit and the skin, which impairs thermal insulation.

For tropical waters, where the temperature is higher, in addition to the suits of fine neoprene, there are also facts in synthetic materials (Lycra, Darlexx, etc.). This type of materials does not have the buoyancy of the neoprene and also does not have the same insulating capacity. They are facts that allow a great freedom of movement to the diver, providing some thermal protection and are a good protection of the skin against undesirable contacts.


They are actually wet suits (not 100% watertight) of a piece, to which are applied some attributes used in dry suits, namely a watertight closure, in order to reduce to a minimum the water intake. Also, this type of fact should settle as a second skin (fair, but not tight) to have maximum effectiveness.


They’re completely watertight. They have elastic seals on the neck and wrists (neoprene, latex or silicone), the clasp is watertight and the boots are part of the suit. In this way, the body remains dry, inside an air cushion.

Through a hose, connected to a low-pressure output on the 1st floor of the set of regulators, it is possible to inject air into the suit in a controlled manner. This allows compensating for the decrease in the internal volume of the fact due to increased pressure, thus preventing the tissue of the fact to compress against the skin and becoming uncomfortable.

Just as the water does not enter, also the air does not come out. Therefore these suits have an automatic discharge valve, calibrated for a certain pressure, which allows controlling the amount of air inside the suit. The valve also allows excess air to be purged in case of error or defect in the injector valve, thus avoiding an abnormal filling of the suit.

Dry suits can be made in neoprene, or materials with little thermal protection. In this case, it becomes necessary to wear thermal clothing inside.

These facts are much more expensive than the wet and semi-dry suits, requiring greater care in their conservation.


The basic care in maintaining the isothermal suit is the usual: pass through fresh water and dry in the shade.

The suit should be stored without being folded, to prevent the creases in the neoprene from crushing the small cells, which reduces the insulating power.

The ideal is to store it hanging on a non-metallic hanger and wide support, bearing in mind that the fasteners should be particularly well washed to remove all the salt they may contain.