Buoyancy control in freediving

Secrets of buoyancy control in freediving

Freediving is both an art and a science of diving depths without the use of breathing apparatus. One of the key aspects that allows a freediver to interact harmoniously with the aquatic environment is buoyancy control. Understanding how to control one's buoyancy provides the freediver with the ability to move vertically and horizontally with minimal energy expenditure, increases the safety of the dive, and enhances the enjoyment of the process itself.

Understanding Buoyancy

Buoyancy is the upward force that acts on any object in a fluid, equal to the weight of the fluid displaced. In the context of freediving, buoyancy control is the diver's ability to change their position in the water while remaining relaxed and conserving oxygen.

Neutral Buoyancy

To find neutral buoyancy in freediving, it is important to conduct a test at a specific depth, which for recreational diving is usually set at 10 meters. At this depth, you should achieve a state where you neither rise to the surface nor sink further, meaning you remain still in the water. To check for neutral buoyancy, one must descend to the set depth, grasp the dive line, form the "OK" sign, and observe their position for approximately 10 seconds. If you maintain your position without any additional effort, then the neutral buoyancy is set correctly. With our students, we study and practice this skill during freediving courses.

Buoyancy Adjustment

Freedivers use several techniques to manage buoyancy:

Weight System

The most common method to control buoyancy is the use of additional weights. Determining the exact amount of weight requires experience, as excess will lead to excessive submersion, and a deficiency will lead to excess buoyancy. The weight should be distributed in such a way that the diver maintains a horizontal position in the water.

Breathing Technique

Breath control is a key element of freediving. A deep inhale increases buoyancy, while a full exhale decreases it. While divers usually submerge on a full breath, athletes also use the "packing" technique, where additional air is added to the lungs. In some cases, this amount can be quite significant, reaching up to 1 liter. This is done not to increase the duration of the dive but to make equalizing ear pressure easier. It is important to understand that buoyancy will also increase, and this should be taken into account. Sometimes in freediving, a technique called diving to FRC (functional residual capacity), or passive exhalation, is used. This is a special technique for training, which we will not detail in this article, but it is important to understand that a diver's buoyancy will be lower after exhaling air from the lungs, and ascending from depth will be more difficult. In other words, increasing lung volume after a deep breath increases buoyancy, while decreasing lung volume during exhalation makes the freediver less buoyant.

Body Position and Hydrodynamics

An elongated body position reduces water resistance and allows for easier buoyancy control, while a bent body increases resistance and can cause instability. A proper hydrodynamic position helps to conserve energy and allows the diver to maintain a vertical position in the water, which is important for managing movement and reducing effort during descent and ascent.


The thickness and material of the wetsuit affect buoyancy. Neoprene has a foamed structure that increases buoyancy. Therefore, when choosing a wetsuit for freediving, these factors must be taken into account, and if necessary, the amount of weight adjusted. For instance, a 3mm thick suit will require less weight than a 5mm suit.

Practical Application of Buoyancy in Freediving

  • Dive Initiation. At the beginning of a dive, a freediver must overcome positive buoyancy to start descending. This requires some effort. The ideal method is to make a powerful effort using both arms and legs to initiate downward movement, after which buoyancy decreases with increased depth and the compression of the lungs under water pressure.
  • Mid-Dive. Once the freediver reaches the point of neutral buoyancy (usually at a depth of about 10 meters), they no longer need to actively move to descend. The body begins to sink naturally due to reduced buoyancy. Here, it is important to relax and allow gravity to do its work, minimizing movements and conserving energy.
  • Freefall and Turn. At greater depths, buoyancy becomes negative, and the freefall stage begins, where the diver relaxes and glides downward, maintaining the correct body position and monitoring timely pressure equalization in the middle ear and mask if the dive is done with a mask. This process continues until the diver reaches the planned depth. Then follows the turnaround and the beginning of the ascent.
  • Ascent. During the ascent, the freediver must take into consideration the changing buoyancy. As they approach the surface, where the pressure decreases and buoyancy increases, efforts can be reduced and natural buoyancy of the body can be allowed to aid in the ascent.


Buoyancy management in freediving is a complex skill that requires practice and understanding. The better a freediver controls their buoyancy, the safer and more enjoyable their dives will be. This is achieved through the correct choice of equipment, diving tactics, body position, and practical skills. Buoyancy management not only increases the safety of the dive but also allows the freediver to experience an incredible feeling of unity with the aquatic element.

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