Thursday, November 30, 2023

Easy 3-Part Guide to Watching a Freediving Depth Competition – Part 1: Need-to-Know Terms


With the rising popularity of Diveye, a fully integrated underwater drone system, more freediving competitions are becoming accessible to the general public from the comfort of their homes. Not only are people all around the world able to watch competitions live, they also have an advantage that even divers watching the competition in the water do not have: they can watch complete video footage of the dive from beginning to end, and even see an athlete’s performance at depth. This is an incredible technological feat, and with it, competitions like Vertical Blue that stream live have more viewers than ever before, including people who are not familiar with freediving competitions (or unfamiliar with freediving in general)!

If you are planning to watch a freediving depth competition for the first time, or have had the opportunity to watch one and want more understanding of what is going on, this three-part guide is for you! The first part of the guide will give you useful terms and their definitions used at competitions regarding freediving record governing associations, depth disciplines, equipment, techniques, injuries, and competition-specific terms. The second part will cover competition organization, how athletes are judged, and the penalties they may face. The third part will give you a background on the safety team behind each competition and how they ensure the safety of the athletes.

Let’s take a look at common terms you hear during a freediving competition.

Freediving depth disciplines and record governing associations

Alexey Molchanov ascending with no fins. Photo by Daan Verhoeven.
Alexey Molchanov ascending with no fins. Photo by Daan Verhoeven.

While there are freediving disciplines that are specific to pool and certain depth disciplines that are specific only to certain freediving organizations, the disciplines listed below are the most common depth disciplines regulated by the two most well-known freediving record governing associations, CMAS and AIDA. These organizations are separate and do not recognize each other’s world records and have their own set of competition regulations.

Freediving record governing associations

  • CMAS – Short for Confédération Mondiale des Activités Subaquatiques (English: World Underwater Federation), CMAS was founded in 1959 by subaquatic explorer and documentary filmmaker Jaques-Yves Cousteau. The organization ratified most of the early achievements made by freedivers, although they stopped holding competitions and ratifying records in the late 1970s due to a few serious accidents. CMAS resumed ratifying records in 1995.
  • AIDA – Short for Association Internationale pour le Développement de l’Apnée (English: International Association for the Development of Apnea), AIDA was created in 1992 to formulate a stable and safe set of rules and guidelines for competitions and record attempts. AIDA is now an international federation and is the single largest organizer of international freediving competitions, rules, and regulations.

Freediving depth disciplines

  • Free Immersion (FIM) – A freediving depth discipline where the freediver pulls down the dive line and then back up using the same amount of weight (on the neck or hips) throughout the entire dive. The freediver does not wear fins.
  • Constant Weight (CWT) – A freediving depth discipline where the freediver uses bifins or a monofin to propel themselves down the dive line and then back up using the same amount of weight (on the neck or hips) throughout the entire dive.
  • Constant Weight Bifins (CWTB) – A freediving depth discipline where the freediver can only use bifins to flutter kick down the dive line and then back up using the same amount of weight (on the neck or hips) throughout the entire dive.
  • Constant Weight No-Fins (CNF) – A freediving depth discipline where the freediver uses arm strokes and leg kicks to propel themselves down the dive line and then back up using the same amount of weight (on the neck or hips) throughout the entire dive. The freediver does not wear fins.


Freediver resting at the surface with a buoy and the dive line freediving competition

While competition equipment depends on the competition itself and the discipline an athlete is competing in, below are the most popular types of equipment seen in freediving depth competitions, both personal equipment that competitors wear and the equipment used in competition.

Personal freediving equipment

  • Mask – A freediving mask is a diving mask that covers the nose with a low internal volume and a soft skirt, allowing freedivers to pinch their nose and equalize their ears and the air spaces inside the mask.
  • Nose clip – Freedivers use nose clips to keep water from entering their nostrils while also allowing them to equalize hands-free. They cannot be worn with a mask; instead, they are worn with fluid goggles, self-equalizing goggles, or with a bare face. Athletes in competitions usually wear a nose clip instead of a mask, as equalization and staying streamlined is much easier with a nose clip.
  • Fluid goggles – Fluid goggles are goggles that are designed to be filled with water so that air spaces around the face are eliminated. They have a special glass that allows freedivers to have some vision underwater so that they can keep their orientation around the dive line.
  • Self-equalizing goggles – Similar to fluid goggles, except that the skirt on self-equalizing goggles is highly flexible, which allows compression under pressure and eliminates the need for water inside. They give the wearer crystal-clear vision underwater. The only self-equalizing goggles on the market at the time of this writing are the Hektometer freediving goggles.
  • Neck weight/weight belt – Weights are used in freediving to compensate for positive buoyancy and to help aid the descent of a freediver after 10m (33ft or deeper). They can be worn on a belt around the waist or are made as a weighting system worn around the neck.
  • Dive computerDive computers are used by freedivers to monitor stats such as their current depth, maximum depth, dive time, surface interval time, and allows them to set alarms for their dives at certain depths.
  • Lanyard – A freediving lanyard is an important piece of safety equipment that keeps a freediver tethered to the dive line and prevents them from getting lost in the open water. They can be attached at the wrist or ankle, and some freedivers choose to wear lanyards with belts for no-fins performances. A competition-approved lanyard must be used during the competition.
  • Wetsuit – Freedivers use wetsuits to protect themselves from the sun, offer thermal protection, and protects from stinging creatures in the water. There are many different styles of wetsuits that freedivers have to choose from.
  • Bifins – Fins that are designed specifically for freediving, with longer blades and soft foot pockets.
  • Monofin – A single fin that attaches to both feet, requiring a special technique to operate that gives freedivers more speed and power to dive longer distances.
  • Flashlight – During the competition, deep freedivers may wear a flashlight attached to the top of their hood. They do this so that they can see the dive line and keep their orientation, even when it becomes very dark at depth.

Freediving competition equipment

  • Dive line – The line that an athlete dives on. It is attached to a buoy, diving platform, or boat at the surface at one end, and has a heavy bottom-weight attached to the other end, keeping it taut. Located above the bottom weight are a bottom plate, the candy cane zone, and a stopper. Additionally, there is a bright light placed at the bottom so that the divers can see the bottom plate and tags.
  • Bottom plate – A plate holding multiple tags attached with velcro that is located at the end of the dive line above the bottom weight.
  • Tag – Tags are attached to a bottom plate near the end of the line, and the athlete grabs one at depth to bring it back to the surface and show the judges. Athletes keep the tag in their hands, tuck it into their hoods, or even put a patch of velcro on their wetsuits so they can stick the tag on easily.
  • Candy cane zone – A 2m (7ft) zone located on the dive line below the rope stopper and above the bottom plate. It is marked with stripes, giving it the appearance of a candy cane, and signals athletes that they are approaching the end of the line. They are allowed to grab the line anywhere in this zone to grab the tag, turn, and make their first pull on the ascent (in CWT, CWTB, and CNF, it is the only place an athlete can grab and pull the line without getting penalized).
  • Stopper – A round or cone-shaped attachment at the end of the dive line and above the candy cane. It is there to keep the freediver’s lanyard from reaching the very end of the line and entangling with the bottom weight.
  • Counter ballast system– A safety system consisting of pulleys and a very heavy weight that deep freedivers use to retrieve a freediver at depth in case of emergency. When a freediver is at depth and wearing a lanyard, the heavy weight attached to the opposite end of the line is released, allowing the freediver to be pulled back up to the surface quickly to initiate rescue procedures.


Freediver dolphin kicking using a monofin
Freediver dolphin kicking underwater using a monofin.

This guide is meant to give a general overview of techniques that are often discussed during freediving competitions. For more in-depth knowledge on freediving techniques and to learn proper technique yourself, it is recommended to take a certified freediving course from an experienced instructor.

  • Bifin technique/flutter kick – A freediving technique with bifins where the freediver performs alternating rapid up-and-down movements to propel themselves forward. Athletes who are competing in CWTB may only use a flutter kick to propel themselves; if they use a dolphin kick, they will be disqualified.
  • Monofin technique/dolphin kick – A freediving technique using a monofin where the core, hips, and legs move up and down in an undulating movement to propel a freediver forward. The movement looks similar to the way that dolphins use their tails to swim underwater.
  • Freefall/Sink phase – The point in a dive when, after reaching negative buoyancy, the freediver stops movement and glides the rest of the distance to the bottom in a streamlined position while staying parallel to the dive line. This is where they focus on relaxation and minimize their oxygen consumption by reducing movement.
  • Frenzel equalization/technique – An equalization method that uses the tongue to force air into the mouth and against a pinched nose, which creates air pressure and equalizes the middle ear.
  • Mouthfill equalization/technique – An advanced equalization method freedivers use to equalize to depths deeper than 40m (131ft). It uses a specific technique that requires drawing air into the mouth from the lungs and using oral muscles to equalize.
  • Recovery breathing – A recovery technique where quick, active inhalations are followed by passive exhalations. They are performed directly after a breath-hold is completed in order to quickly restore oxygen levels and decrease carbon dioxide levels.
  • Hyperventilation – Manipulating breathing to allow more air in and out than the body needs. This technique is not recommended or used by recreational freedivers and is not commonly used by competitive freedivers as it can lead to a loss of consciousness (blackout).
  • Lung packing – Also known simply as “packing,” it is an advanced technique that is not recommended unless you are an advanced freediver that is being given guidance and should not be used by recreational freedivers. It uses the muscles of the mouth and throat to take additional air into the lungs after the final breath.

Possible injuries in competition

safety team freediving competition
A freediving competition safety team running a practice drill at Vertical Blue 2015.

Keep in mind that this is not a comprehensive list of all the injuries that could possibly happen during a competition, just the ones that are more commonly talked about during a freediving competition. Competitions are generally the safest place for freediving athletes as there is a trained safety team, qualified medical personnel, and an emergency evacuation plan and/or vehicles in place. Freediving athletes also train extensively and are very knowledgeable, so the risk of pressure-related injuries can even be considered as more minimal since they approach deeper depths with knowledge and a certain level of preparedness.

  • Contractions – Contractions are not an injury and are a very natural part of freediving. They are an involuntary spasm of the diaphragm that pushes against your lungs to make you breathe, and is a result of carbon dioxide building up in your body. As freedivers approach the end of their breath-hold, contractions get stronger and more frequent, and they are used as a signaling system for freedivers to know where they are in their breath-hold.
  • Loss of motor control (LMC) – A late warning sign of very low oxygen levels that only occurs on the surface. A freediver’s muscles spasm and jerk, but resolve once they breathe and restore a sufficient level of oxygen. If a freediver does not breathe on their own and oxygen levels continue to decrease, a full loss of consciousness (blackout) occurs.
  • Blackout – A loss of consciousness due to insufficient levels of oxygen in the body. Blackouts in freediving are more likely to happen on the ascent between 10m (33ft) and the surface due to the sizable drop in the partial pressure of oxygen.
  • Lung barotrauma/squeeze – Damage or injury to the lungs due to pressure, which can occur if the freediver is not fully relaxed or if diaphragm flexibility is an issue. In freediving, this injury is commonly referred to as a “lung squeeze.”
  • Perforated/ruptured ear drum – A pressure-related injury where a hole or tear in the thin tissue that separates the outer ear from the middle ear occurs. This can happen if a freediver cannot equalize but continues their descent. Also known as ear barotrauma or a “middle ear squeeze” in freediving.
  • Lung overexpansion – An injury that can occur when freedivers pack extra air into their lungs and do not exhale some of the air near the surface on the ascent. This can also occur if a person dives down on a breath-hold, takes a breath from a scuba diver’s regulator, and ascends without exhaling the air; certified freedivers are taught never to do this, but it regrettably happens to people with no background freediving knowledge or education.

Competition-specific terms

Freediving athlete Alenka Artnik performs surface protocol after finishing a competition dive. Photo by Daan Verhoeven.
Freediving athlete Alenka Artnik performs surface protocol after finishing a competition dive. Photo by Daan Verhoeven.
  • Top time/Official Top – An athlete’s official time of performance in a competition.
  • Surface protocol (SP) – A set of actions an athlete must execute to show the judges that they capably performed the dive within their personal limits. Within 15 seconds of surfacing, athletes must look in the direction of the judges, remove their facial equipment, show the “OK” sign with their hand, and say “I’m OK” in English while remaining upright and avoiding letting their airways dip below the water for 30 seconds. Different organizations have different orders of actions or specific time limits, but the actions that need to be performed remain the same.
  • White card – Clean performance with no penalty points. Only white card performances can become national or world records.
  • Yellow card – Clean performance but with some penalty points.
  • Red card – Performance is disqualified.
  • National record (NR) – The deepest performance made by an individual for their country that was made according to an organization’s rules and presided over by the organization’s judges.
  • Official world record (WR) – The deepest performance made by an individual worldwide that was made according to an organization’s rules and presided over by the organization’s judge/s that are authorized to oversee world record attempts. The athlete has passed the anti-doping drug test given by WADA (World Anti-Doping Agency).
  • Pending world record – The deepest performance made by an individual worldwide that was made according to an organization’s rules and presided over by the organization’s judge/s that are authorized to oversee world record attempts. The athlete has not yet received the results of the anti-doping drug test given by WADA.
  • Unofficial world record – The deepest performance made by an individual worldwide, but occurred outside a WR status competition.
  • WR status competition – A competition with world record status means that at least one managing judge of the competition is at a level that allows them to certify world record performances.

Stay tuned for the second part of the guide, which will cover competition organization, how athletes are judged, and the penalties they may face.

Feature photo by Daan Verhoeven

Kristina Zvaritch
Kristina Zvaritch
Kris is an AIDA/Molchanovs Freediving Instructor, freelance copywriter, and one of the founders of SaltyMind Freediving on the little island of Xiao Liuqiu, Taiwan. She has written 100+ articles centered around freediving for and co-authored the Molchanovs Wave 4 - Competitive Freediving manual. When Kris isn't writing or teaching freediving, you can find her floating on a wave at the beach or struggling to learn Mandarin on land.