After having thoroughly analyzed the construction details and materials of the new C4 Dyn-UP Competition freediving wetsuit, we wanted to test it in its natural environment: the swimming pool. Taking charge of this test is Luciano Morelli, an athlete who certainly doesn’t need an introduction. Luciano is a member of the Apneapassion International Team, and can claim a very respectable palmares, such as extremely podium results at an international level, both in DYN and DYNB. Luciano deeply tested this wetsuit and has formulated an exhaustive report.

Quick and easy to wear

Wearing the C4 Dyn-UP Competition wetsuit is undoubtedly facilitated not only by the internal fabric, but also by the material softness and the presence of the thinner inserts. The wetsuit can easily be worn at the poolside and without using water. With a wet body, putting on the wetsuit may be less easy and, in these cases, it is advisable to wet the wetsuit as well.

Given the smooth external surface of the Glide Skin Neoprene, undressing should always be made easier by wetting the wetsuit inside the pool or under the shower, but this is also not complicated.

The described ease in putting on and taking off the C4 Dyn-UP Competition, and also the internal reinforcement strip placed at the joints of the various “patches”, should not, however, lead us to be excessively offhand. We must always keep in mind that the ends of the lower limbs, the sides and the arms are made of material only 0.5 mm thick and that a small distraction could put us at risk of piercing it with our own fingers.

Once you have worn the wetsuit for the first time and checked that it fits without creases or twists in the sleeves and legs, remember that it is possible to adjust the length at the sleeves and legs, by cutting off the excess centimeters.

Soft and elastic, the C4 Dyn-UP Competition dresses like a glove

Once worn, the C4 Dyn-UP Competition stands out for its extreme elasticity and softness and for the 0.5 mm thick inserts on the shoulders, arms, side bands, crotch and legs below the knees. The thicker 2 mm parts used for the torso do not create constraints and allow for easy expansion of the chest. Once the rear zip is closed and the Velcro is tightened, the sensation of waterproof insulation is clear. Luciano describes to us a sensation of “compactness” on the body with the wetsuit of the size suggested by C4 Carbon. The use of this wetsuit also in a swimming test left our Luciano very satisfied in terms of fit. As regards the use in dynamic apnea sessions, Luciano preferred to use a smaller size than that recommended by the manufacturer, to obtain a compression effect which brings advantages in terms of hydrodynamics.

Optimized neck closure

Overall, the wetsuit fits very snugly and comfortably, but Luciano, 178 cm tall and weighing 75 kg, preferred a size 1 C4 Dyn-UP to the size 2 he normally wears.

However, even in this configuration what surprised was, without a doubt, the closure of the neck for which the C4 Dyn-UP Competition made a notable leap forward compared to the previous freediving suits from the Lombard company. This has significantly limited the water infiltrations, which are not noticeable, however until you do high speed sessions, with a monofin, for example, mainly due to the softness of the material. However this is a problem we found in all similar products. It is no coincidence that speed or endurance athletes prefer to use costumes in these disciplines.

Freedom of movement and warmth

Luciano was very satisfied with the absolute freedom of movement, thanks to the 0.5 mm inserts designed to maximize motility: the bands on the sides that go up to the armpits and continue along the arms, in particular, provide their benefits in free swimming and in the DNF (dynamic no fins) specialty. Additionally, the presence of these thinner parts does not compromise thermal insulation which, thanks to the wise placement of the 2 mm thick parts, allows the body temperature not to be lost and guarantees exceptional thermal comfort.

Reduced ballast

One other key element of the C4 UP-Dyn Competition freediving wetsuit is the fact that the differentiated thicknesses of the neoprene sheets reduce buoyancy compared, for example, to a 2 mm thick solution. Even though the weights used during the dynamic performance in the pool are also strictly linked to the physique and lung capacity of each single athlete, there is indeed a delta in the ballast which depends on the wetsuit thickness. Luciano has made a comparison between the C4 Sideral, which is constant 2mm thick neoprene, and has reduced the weight from 6.600 Kg to 6.030 Kg.

The stress test at sea

Lastly, Luciano wanted to try this wetsuit to a super test, stressing it over a long distance of 6 km of swimming, in open water, in the sea. The C4 Dyn-UP Competition performed really well: the presence of parts with the lower thickness of 0.5 mm, favors the swimming gesture without tiring the limbs, which can happen even with common differentiated thicknesses Triathlon wetsuits. Fluidity of movement and absence of resistance to the stroke are the characteristics noted by Luciano. Sliding in the water was also a strong point of this wetsuit. On the other hand, the 2 mm thick parts also make their contribution, with their thermal insulation and their good buoyancy.


The price to the public of the C4 Dyn-UP Competition is 359€. It is definitely a high price, but also completely justified by the high level technical solutions of this new product. We do not know if it will have a special price at the launch, which will be end of December 2023 – beginning of January 2024.

Likes and dislikes in C4 Dyn-UP Competition wetsuit


  • Innovative: the C4 Dyn-UP Competition is the first Indoor Freediving wetsuit that can also be used for swimming;
  • -Freedom of movement both in dynamics with fins (DYN) and in DNF;
  • -Excellent glide in the water;
  • -The differentiated thickness allows you to limit the use of ballast in the pool and, especially in DNF, allows a more horizontal trim thanks to the reduced thickness on the ends of the two legs;
  • -Attractive design;

Like less

  • -Using the size recommended by C4, the wetsuit may be a little large at the lumbar height;
  • -The wetsuit, although not expressly designed for this use, could take-on water during a speed or endurance test. The customer who, with a single wetsuit, wants to dedicate himself to both dynamics and speed disciplines, may not find it functional;
  • -It is clear that the 0.5 mm thick neoprene areas are more delicate
  • -The price of 359€, justified by the high quality and technical solutions, is for some but not for all