Open Menu

Safety during freediving

General public takes freediving for a demanding, dangerous and adrenalin sport. But freediving has actually nothing to do with adrenalin at all, but only on condition that a freediver adheres to the basic safety rules.

Even if it does not seem so at first sight, freediving is in many aspects even safer than recreational scuba diving, not to mention technical diving. Many people of all ages do freediving and snorkeling especially in summer during holidays. The basic difference between a freediver and a snorkeler beside equipment is that snorkelers dive with a snorkel in their mouth, whereas a freediver always moves under water without it. He prevents thereby water from entering his mouth and from eventual breathing water in during diving, for instance during a strong contraction of the diaphragm (contraction of the diaphragm caused by an increased concentration of CO2 in the body). Bad breathing out of a snorkel on the water surface can cause breathing water in and a spasm of the vocal cords, which inhibits breathing. It can cause unconsciousness (black out). A snorkel in the mouth needlessly complicates situation in case of loss of motor control due to lack of oxygen (known as samba or LMC – loss of motor control) or during blackout. In addition to that it significantly complicates pressure equalization in greater depths, but this is a different issue.


The first thing a person interested in freediving should consider carefully is health. It is not just about how he feels, but about an objective examination by a doctor. Many people suffer today from serious health problems due to lack of exercise, excess of psychological stress, environmental changes and changes in food quality – such as heart attack, diabetes or cerebral vascular attacks afflicting even young people. A diving reflex activates during demanding freediving, which means additional physiological stress. An intensive psychological stress and related physiological processes appear in crisis situation in addition to that. Therefore we strongly recommend a person interested in freediving to undergo a medical examination by a sports doctor including a stress test, diving reflex and ORL. The medical examination must be repeated in case of change in health or after a consultation with a general practitioner. A freediver over 40 years who has no health problems should repeat the medical examination at least each five years.

Good physical and psychological condition is a big advantage. A proficient and trained person copes with greater stress in general, enjoys nice moments in the water more and it is easier for him to manage crisis situations. A prerequisite is a regular training, which should include practice of crisis situations.


Diving safety has also much to do with choice of appropriate equipment. Choice of the right suit ensures thermal comfort and we will avoid hypothermia or overheating. Both states can restrict our capabilities and performance. Regular supplying with liquids during diving is also related to that. Sufficient hydration of organism is very important, especially in the areas with higher temperature of water and air. Every freediver should have a knife or rather a cutter for ropes and strings. Quality knives can cut off even thin steel ropes and thereby they can save a life. Unlike scuba divers, there is just a minimum time for extrication during freediving. We usually have a cutter on the belt or in the hand. It is a matter of course to check the state and functionality of our equipment regularly!



Before we enter the water, we should obtain at least basic information about the location and find out what is interesting there and what the other diving conditions are. We care for water temperature, strong water currents, high tide and low tide, remains of fishing nets and fishing lines, intensity of water traffic, but also dangerous animals occurring in the location. According to these information and our experience we can prepare responsibly for diving and plan and secure everything. Before the event we should report to our family or to the base where we are going diving and when we plan to come back. It is important to mark a diving place with a well visible buoy with a diving flag. The flag can be also on the boat. Non-observance of this basic rule is fined in many countries. Divers should not move away from the buoy at a greater distance than 25 metres. This is supposed to be a safe zone for a diver, which passing boats and ships must avoid. But experience shows unfortunately that even marked places of diving do not guarantee one hundred per cent safety. It is not easy for a driver of a speedboat to spot a coloured buoy in the waves, not to mention heads of freedivers. Therefore we prefer to avoid places with heavy boat traffic, especially in bad wind conditions.


Correct balancing of the freediver for the given location is also very important. If we dive on the walls where we cannot see the bottom (Only for experienced freedivers or with an experienced guide!), we balance ourselves so that we were neutral at a greater depth. Thereby we avoid the risk of falling on the water surface. This value is only approximate and it depends on many variables. Correct balancing for the concrete depth saves a large amount of energy, it extends a period of dives and it contributes to greater safety. We should not be too lazy to add or take off loading whenever it is necessary. Deep training on the rope requires different balancing than diving for pleasure in places with maximum depth 10 m. A different loading is needed for the same level in fresh water and in salt water…



The principle number one for racing and recreational freediving is so-called buddy system, i.e. the rule „Never dive alone!“ A partner (buddy) should be a qualified, experienced freediver sufficiently fit according to the conditions of the conducted dives.

Many people unfortunately break this rule and it might have fatal consequences. How does a well-functioning buddy system look like? A wife or a child on a beach or on an inflatable sunbed far from you is definitely no buddy and an argument that you dive just a little bit and that you do not go to the edge of your opportunities cannot be accepted. It is not just a question of depth and length of dives, but also a question of the current state of your body and of conditions that you cannot anticipate. A sudden weakness can afflict everybody for various reasons. It might be for instance a beginning infection already negatively influencing functions of your body or circulatory problems caused by overheating in combination with dehydration. When coming out of water you can hit your head on the boat, about which you don’t know, or you can be simply run over by a distracted windsurfer or a kiter.


The best buddy is a person we know well. We know his or her physical condition, we know each other’s limits, reactions, way of moving etc. We will agree in pairs how we will dive. If partners do not know each other well, I recommend change of basic information about certification and experience, to which a dive plan can be adapted. We proceed in the water as follows: The first person of the pair dives in, the second person observes him or her from the water surface and then swims after him or her so that he or she is close to the partner when diving out and observes him or her breathing on the water surface. Only after half a minute from diving out they will confirm each other that everything is OK and then they will swap roles.

An advantage of the close buddy system is that in case of problems both above and below the water surface we are able to intervene quickly and effectively. We will recognize any hesitation in time and give the freediver first aid. Simple rescue is known under the name BTT (blow, touch, talk). In the first place it is important to prevent water from entering the airways of the afflicted person. It means that his or her mouth after diving out must not get into the water again. Then we lay him with the back on the water surface and take his or her mask off. By blowing to the exposed face and by lightly touching the face with the hand we affect nerve endings in this area. While doing all this we talk to him or her with a calm voice till the moment when he or she regains consciousness.

Most cases of unconsciousness or loss of motor control caused by hypoxia during diving on the open water happen on the water surface or only at shallow depths just below the water surface. Total pressure drop during rising to the water surface means a dramatic drop of partial pressure of oxygen in the freediver’s body. If a diver loses consciousness, but is well balanced, positive buoyancy brings him up to the water surface, where a buddy looks after him. Such „accidents“ take usually just a few seconds and an afflicted freediver does not have any negative experience of it. But if he was diving alone, the same case would have fatal consequences. So let us repeat the most important rule: „Never dive alone!“


WARNING: The article states some risks associated with recreational freediving. It serves as information, but it cannot substitute a quality training led by an experienced, certified freediving instructor!



Diving in wrecks, manholes and caves is a beautiful, but a very demanding form of freediving, which is not advisable to begin without supervision of an experienced instructor. Risk of interception and impossibility of direct coming up to the water surface puts high demands on freediver’s abilities. Perfect knowledge of the given location is also very important. In Czech waters we can find under water diving bells, so-called kessons. Air is usually exchanged in them on the diving bases, and breathing in a kesson is quite safe then. But we have to make sure whether there is a fresh air in the kesson before we dive in. One breath in a kesson means that the air we breathed in for instance at the depth of 10 m will expand to the double amount when coming up to the water surface. Freediver must therefore breathe it out continuously so as to avoid lung damage caused by overpressure (barotrauma), which can have fatal consequences.



According to AIDA CZ, a freediver has to know and respect that...

1. He must not dive without direct protection by at least one protecting diver both on the free water and in the swimming pool. He plans dives together with the protecting diver and other team members. They will discuss especially communication, crisis management etc.

2. Diving equipment must be functional and purposeful for the planned dive. Basic duty is sufficient familiarization with the equipment, verification of functionality and control of equipment before dive.

3. It is strongly recommended to finish diving on the given day, if the diver suffered a loss of consciousness (blackout) or loss of control over motor activity (samba).

4. He is supposed to maintain continuously his diving skills and physical and psychological condition. He can prevent accidents by practicing his freediving techniques and their development in a controlled environment and under the expert guidance.

5. He is supposed to be familiar with his health condition and not to overestimate his forces.

6. Freediving is strongly dissuaded to divers, whose physical or psychological abilities are reduced by a disease, alcohol or drug consumption, fatigue etc.

7. The diver is supposed to familiarize oneself in detail with the current location and its specialities.

8. Freediving is strongly dissuaded to freedivers in caves, wrecks, under the ice or in other spaces with a limited possibility of direct coming up to the water surface without knowledge of the location and perfect safety assurance.

9. It is strongly recommended to have a permanent overview of the current depth. He has to adjust both depth and dive time to his skills and experience.

10. The diver has to be balanced so that he comes up to the water surface even during full breathing out. The loading system must be easy to unbutton and thrown away with a single hand movement.

11. Is supposed to keep sufficient surface intervals between the individual dives.

12. It is good to familiarize oneself with the local rules and regulations about diving and freediving in the given location.