thumb|A freediver on the ocean floor

Freediving, free-diving, free diving, breath-hold diving, or skin diving is a mode of underwater diving that relies on breath-holding (apnea) until resurfacing rather than the use of breathing apparatus such as scuba gear.

Besides the limit of breath-hold, immersion in water and exposure to high ambient pressure also have physiological effects that limit the depths and duration possible in freediving.

Examples of freediving activities are traditional fishing techniques, competitive and non-competitive freediving, competitive and non-competitive spearfishing and freediving photography, synchronised swimming, underwater football, underwater rugby, underwater hockey, underwater target shooting and snorkeling. There are also a range of competitive apnea disciplines; in which competitors attempt to attain great depths, times, or distances on a single breath.

Historically, the term free diving was also used to refer to scuba diving, due to the freedom of movement compared with surface supplied diving.

Modern spearfishing makes use of elastic powered spearguns and slings, or compressed gas pneumatic powered spearguns, to strike the hunted fish. Specialised techniques and equipment have been developed for various types of aquatic environments and target fish. Spearfishing may be done using free-diving, snorkelling, or scuba diving techniques. Spearfishing while using scuba equipment is illegal in some countries. The use of mechanically powered spearguns is also outlawed in some countries and jurisdictions. Spearfishing is highly selective, normally uses no bait and has limited by-catch.

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| align="left" bgcolor="#f2f2f2" | Skandalopetra || depth & min. time || colspan="2"| || || –

| align="left"| The only true team event in freediving. Diver 1 descends, usually assisted by a stone or marble slab attached to a rope, while Diver 2 waits on the surface. Diver 1 reaches the target depth and is hauled to the surface by Diver 2 using only muscle power. No diving mask, suit or fins are permitted, only nose clip.

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| align="left" bgcolor="#f2f2f2" | Static apnea (STA) || max. time || || || ||

| align="left"| Timed breathhold endurance while floating on the surface or standing on the bottom. Usually in a pool.

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| align="left" bgcolor="#f2f2f2" | Static apnea with pure oxygen (STA O<sub>2</sub>) || max. time || colspan="2"| || colspan="2"|

| align="left"| Timed breathhold endurance, pre-breathing 100% oxygen for up to 30 minutes prior to the breathhold is permitted. Usually in a pool. Although no longer recognised by either AIDA or CMAS there were three instances of records being approved by AIDA.

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| align="left" bgcolor="#f2f2f2" | Speed-endurance apnea (S&E apnea)

Physiology

Human physiology of freediving is the physiological influences of the underwater environment on the human breath hold ambient pressure diver, and adaptations to operating underwater. It, therefore, includes the range of physiological effects generally limited to human freediving. Several factors influence the diver, including immersion, exposure to the water, the limitations of breath-hold endurance, variations in ambient pressure, and sensory impairment. All of these may affect diver performance and safety.

Safety

Freedivers are encouraged by certification and sporting organisations to dive only with a 'buddy' who accompanies them, observing from in the water at the surface, and ready to dive to the rescue if the diver loses consciousness during the ascent. This is only reasonably practicable if the water clarity allows observation, and the buddy is capable of safely reaching the diver. In poor visibility the diver can clip onto the downline with a buddy line. Signals can be transmitted on the downline and it can be used to find the diver. Spearfishers can use a surface marker buoy for the same purpose. Due to the nature of the sport, the risks of freediving can be reduced by strict adherence to safety measures as an integral part of the activity, but cannot be eliminated. Competition rules may require all participants to be certified and adept in rescue and resuscitation.

In case of a deeper incident, the competitor is clipped to the downline for the duration of the dive, which can be rapidly raised by the surface support team, which includes a medical support group.

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Further reading

  • DeeperBlue.com (2016) The Beginners Guide to Freediving, published by DeeperBlue.com
  • Callagy, Feargus (2012) A Beginners Guide to Freediving, e-book published by DeeperBlue.com
  • Donald, Ian (2013) Underwater foraging – Freediving for food, Createspace publishing, USA.
  • Farrell, Emma (2006) One Breath: A Reflection on Freediving, photographs by Frederic Buyle, Pynto Ltd., Hatherley, UK:
  • Pelizzari, Umberto & Tovaglieri, Stefano (2001) Manual of Freediving: Underwater on a single breath, English translation 2004 by Idelson-Gnocchi Ltd., Reddick, FL:
  • Severinsen, Stig A. (2010) Breathology: The Art of Conscious Breathing, Idelson-Gnocchi Ltd., Reddick, FL:
  • James Nestor (2015) "Deep: Freediving, Renegade Science, and What the Ocean Tells Us About Ourselves", Eamon Dolan/Mariner Books New York, NY:
  • AIDA International
  • Collaborative cartography of freediving spots/Cartographie collaborative des spots apnée
  • DeeperBlue website
  • The Beginners Guide to Freediving - published by DeeperBlue.com
  • FreedivingCourses.com - a way to find Freediving instructors and dive centers around the world
  • DiveWise.Org - non profit organization dedicated to freediving education and safety
  • Explore Freediving - Freediving and Snorkeling events and instructor directory
  • Freediving Spots
  • Freedive Central - The ultimate platform for freediving professionals
  • Borgosub.fr French association to promote Wreck freediving
  • Freitauchen-lernen.com - deutschsprachiger Freediving Blog
  • www.apnoetauchen-lernen.de - German Center for education and development of freediving.
  • Freediving blog - Trusted knowledge hub for freediving
  • freedivingbase website - Discover top-rated freediving schools and world-class dive destinations