Freediving Fins and Monofins for Freediving

The fin is the primary propulsion tool in Freediving and freediving. Its geometry, blade material and blade stiffness directly determine the efficiency of each finning cycle, affecting energy consumption and, consequently, bottom times and attainable depths. Deep Blue’s Freediving Fins category includes fins, monofins, replacement blades and foot pockets from leading specialized manufacturers, with a range covering every level of practice: from technopolymer models suited to those approaching freediving for the first time, to carbon blades intended for competitive athletes and advanced freedivers.

The range includes systems with complete fins, blades with interchangeable foot pockets and monofins with an integrated structure, designed for pool dynamics and the CWT (Constant Weight) discipline. Individual blades and foot pockets sold separately are also available, allowing you to upgrade existing equipment without replacing the entire set.

Product types

Interchangeable-system fins

This type is the most common configuration in Freediving and recreational freediving. The two separate blades attach to the foot pocket through a side or center mounting system. This layout allows you to replace only the blades or the foot pockets, optimizing costs over time. The models in this category feature blades available in multiple materials and stiffness levels, suited to different body weights and finning styles.

Monofins

A monofin is a single-blade piece of equipment that connects both feet into one structure. Finning is performed with an undulating body movement called the dolphin kick, which requires a specific technique compared to the alternating kick used with bifins. It is used mainly for pool dynamics (DNF and DYN), but is also used in vertical descents by athletes with well-established technique. Available models include the Cetma Taras and Cetma Lotus, available in both carbon and plastic versions.

Replacement blades

Countless blades are sold as separate components, compatible with foot pockets already owned by the buyer. This solution is especially common among athletes using open systems with cross-brand compatibility, such as DiveR blades made from Innegra, or Pathos carbon blades that fit foot pockets compatible with a standard attachment system.

Foot Pockets

Foot pockets are available sold separately, individually or in pairs, according to supplier policies. 

How to choose freediving fins

Choosing a fin depends on three main variables: the blade material, stiffness, and the type of activity practiced.

Blade material

The material directly affects the blade’s elastic rebound, meaning its ability to recover and transfer into propulsion the energy stored during the loading phase of the kick. Carbon blades offer a high elastic rebound coefficient and low weight, characteristics that result in a more efficient kick for the same muscular effort. Fiberglass blades provide a more progressive response than carbon, with greater tolerance for technical errors; they are a common choice for those refining their technique. Innegra composite material blades - featured in the DiveR range - combine light weight with superior impact resistance compared to pure carbon, making them suitable both for intensive training and for use in environments with rocky seabeds. Technopolymer or plastic blades are the entry-level solution for the discipline: they cost less, are more robust than fiber blades, and are suitable for those developing basic technique.

Stiffness

Blade stiffness is the most critical technical variable when choosing. A blade that is too stiff for the diver’s leg strength will not flex fully during the kick, reducing propulsion efficiency. A blade that is too soft flexes excessively, wasting energy. The correct stiffness depends on body weight, leg strength, and kick frequency. Several manufacturers - especially C4 - offer the same blade in multiple stiffness grades to allow a customized selection.

Discipline practiced

For open-water freediving (vertical apnea, CWT), classic bifins are the most versatile setup. The monofin is the preferred choice for dynamic apnea in the pool, while for pool training there are plastic models with moderate stiffness, such as the C4 Wolverine, suited to continuous finning without the risk of over-fatiguing the muscles. For competitive freedivers or those targeting significant depths, carbon blades — such as the H Dessault range (Fast HD, Pershing HD, Tank HD, Minimal HD) or the C4 MB001 / MB002 — represent the benchmark technical tier.

Size and fit

The fin foot pocket should fit snugly around the foot without leaving empty spaces and without compressing the toes. If using a neoprene sock, you need to account for the added volume and choose a size up from your regular shoe size. Most models in this category are available in a wide range of sizes, with variants covering European sizes from 36 to 47 depending on the brand.

Materials and technical features

Carbon

Carbon fiber is the top material for high-performance freediving fin blades. The carbon blades in this category—C4, Cetma, DiveR Ultra Carbon, Pathos, H Dessault, Sigal Sub Tsunami—vary in blade geometry, blade angle, number of carbon layers, and the type of resin used in the lamination. Cetma, in particular, applies an engineered stiffness distribution method along the length of the blade, with differentiated stiffness zones that allow progressive, controlled flex. DiveR uses high-strength composite materials such as Innegra, a high-performance thermoplastic fiber paired with carbon to increase impact resistance without significantly increasing weight.

Glass fiber (fiberglass)

Fiberglass blades—found in the C4 FBG range (Umberto Pelizzari White and Black)—provide a more progressive flex than carbon. Fiberglass is less stiff and absorbs part of the energy from the fin stroke, making technique less critical but offering lower elastic return. They are suitable for divers who are developing their technique and want a material with a wider margin for error.

Technopolymer and plastic

Plastic or technopolymer models—such as the C4 Umberto Pelizzari line (Aurea, Sideral, Ghost) and the Cetma Lotus Plastic—are made with technical polymers that provide controlled flexibility and impact resistance. They are suitable for learning, pool training, or recreational use. The Cressi Gara Modular Impulse and Mares X-Wing Pro models fall into this range, offering modular systems with interchangeable blades at an accessible price.

Silicone

Silicone is the material used for some foot pockets—such as the Sportech C4—because of its ability to conform to the foot, its resistance to deformation over time, and its ability to maintain uniform contact with the blade during finning. Silicone does not absorb water and does not harden in cold conditions, maintaining consistent properties across different temperature conditions.

Practical use

Open-water freediving – CWT and vertical freediving

For vertical dives in the sea, bifins with medium-length blades (generally 80-95 cm) allow efficient alternating finning during descent and ascent. Choosing the right stiffness is crucial: a blade that is too stiff during descent limits a sustainable finning cadence.

Pool dynamic – DYN and DNF

For pool dynamic, the monofin is the dominant tool in the DYN (Dynamic With Fins) competitive disciplines and is also used in distance training. The dolphin kick requires an integrated body technique that must be developed progressively. For DNF (Dynamic No Fins) and basic pool training, plastic models such as the C4 Wolverine are available with moderate stiffness, suitable for repeated sessions.

Training and technical progression

Those approaching the discipline can start with technopolymer blades—which are less technically demanding—and progressively move on to fiberglass or carbon blades as their finning technique becomes more established. This progression makes it possible to appreciate the behavior of stiff blades without the risk of developing muscular compensations caused by using materials that are too high-performance before acquiring the necessary coordination.

Transport and storage

Blades, especially carbon ones, require careful handling during transport and storage: they must be protected from impacts and lateral pressure that could cause delamination or fiber breakage. For this reason, Deep Blue also offers the Freediving Bags category, with dedicated fin bag and monofin bag models. 

Available brands

C4 is an Italian company specializing in the handcrafted production of freediving fins. The catalog available in this category includes carbon blades (MB001, MB002, L-1090 Freediving, Sportech), fiberglass blades (FBG Umberto Pelizzari and Sportech), plastic blades (Umberto Pelizzari line), and silicone foot pockets (Sportech Silicone). C4 offers the same blade in different stiffness grades, allowing selection based on body weight and leg strength.

Cetma is an Italian company specialized in carbon blade engineering. The models available include the Taras, Lotus (also available in plastic), Prana, and Mantra. Cetma technology stands out for its differentiated stiffness distribution along the blade axis, a feature developed in collaboration with international-level athletes.

DiveR, an Australian company, is represented by a range of blades made from Innegra material - a high-impact-resistant composite fiber - available in Standard, Short, Red, Red-R, and Mermaid Black versions, as well as Ultra Carbon, Carbon Copper Purple, and Carbon Tuna Time blades. The system is sold as blade only and is compatible with third-party foot pockets.

H Dessault with four carbon models: Fast HD, Pershing HD, Tank HD, and Minimal HD. Each model is available in multiple stiffnesses and sizes, meeting the needs of both advanced athletes and intermediate practitioners.

Pathos is represented by three carbon blade models: Nero', Pro Ultimate, and Carbon Maximum, sold as separate components that can be paired with compatible foot pockets.

Cressi is represented by the Gara Modular Impulse in two colorways (Blue Metal and Black), modular-system fins with an interchangeable blade, suitable for intermediate use and for those approaching the discipline with an accessible solution.

Mares is represented by the X-Wing Pro, modular fins available in multiple sizes, with a technopolymer blade that combines flexibility and durability in an entry-level mid-range product.

Sigal Sub is represented by the Tsunami, carbon blades with a competitive performance-to-price ratio compared with the high end of the category.

Conclusion

The Freediving Fins and Monofins category at Deep Blue offers a structured selection covering the full spectrum of the discipline, from technopolymer models suited to first steps in freediving to technical carbon blades from leading brands such as Cetma, C4, DiveR, H Dessault, and Pathos. The availability of blades sold separately, interchangeable foot pockets, and models made from advanced composite materials makes it possible to build a customized setup based on body weight, the discipline practiced, and the technical level achieved. Every product in this category is selected from manufacturers specialized in freediving and competitive freediving, with a range that is continuously updated to follow the evolution of materials and blade geometries used on the international circuit.