Scuba diving dangers, what are they and how to avoid them?
What are the dangers of scuba diving and how can we avoid these risks? Photo by Gerald Lobenwein / Pixabay

Scuba diving is a widely accessible activity that children and adults enjoy. It allows you to breathe underwater while exploring colorful coral reefs, historical wrecks, and see some amazing creatures that you won’t find on-land! However, like with any activity, you should be aware of the very real scuba diving dangers prior to a dive. You should also learn how to avoid them so that you can enjoy this popular sport safely.

Is Scuba Diving Safe?

Firstly, so not to scare anyone, scuba diving is a very safe activity. If you follow the rules.

With any activity, there are dangers and risks involved. This is why scuba diving is listed as an ‘extreme sport.’ However, there are millions of certified scuba divers who enjoy this activity every year, and millions more who get certified each year with various diving agencies. There are children from as young as eight years old who use scuba equipment for a dive in a swimming pool, and there are divers who are over 90 years old still diving shipwrecks.

Learn More: What are the Maximum and Minimum Ages for Scuba Diving?

Scuba diving is extremely safe. However, you do need to know what are the scuba diving dangers and how to avoid them.

Scuba Diving Dangers

Here is a list of scuba diving dangers that can be risky during or after a dive, and how to avoid these dangers.

Decompression Sickness

Decompression sickness (DCS) or ‘The Bends’ as it is also known, is what happens when you go from a high-pressure environment to a lower-pressure environment and you do not decompress properly. DCS occurs when the absorbed nitrogen in your tissues comes out of solution too quickly and creates bubbles in your blood and tissues which can cause blockages that can potentially be fatal.

Read More: What is Decompression Sickness?

How to Avoid DCS

Always ascend slowly, especially at shallower depths. You should also adhere to your No-Decompression Limits when diving recreationally, perform safety stops during the dive, and allow yourself surface intervals between dives. Additional measures to avoid DCS also include proper hydration, being well-rested, keeping a reasonable level of fitness, and avoiding alcohol/drugs prior to diving.

Scuba diving dangers are commonly due to impaired judgement
Always ascend slowly during a dive to reduce your risk of DCS. Photo by Aviv Perets / Unsplash

Lung Over Expansion Injuries

Lung Over Expansion injuries can cause damage to your lungs and be potentially fatal. This occurs when you inhale, hold your breath, and ascend. The air in your lungs will continue expanding due to the reduced pressure as you go up which may cause the following:

  • Pneumothorax – a collapsed lung
  • Mediastinal Emphysema – air trapped between your chest and lungs
  • Subcutaneous Emphysema – air trapped under your skin
  • Arterial Gas Embolism – when an air bubble escapes into the bloodstream blocking blood flow which can be fatal

Read More: What Happens When You Hold Your Breath While Scuba Diving?

How to Avoid Lung Over Expansion Injuries

Never, ever hold your breath during a scuba dive. Always continue breathing, either from your mouth or your nose.

Oxygen Toxicity

Oxygen toxicity is when the oxygen we breathe becomes too poisonous leading to; tunnel vision, twitching, nausea, seizures, or even loss of consciousness. However, the amount of oxygen (21%) in a regular air tank/cylinder will only be toxic beyond 40 m / 135 ft. These depths are beyond our normal diving recreational limits. A tank filled with a higher percentage of oxygen will be toxic at shallow depths which is why you need additional training when using Enriched Air (Nitrox).

How to Avoid Oxygen Toxicity

Dive within the normal diving recreational limits and only dive with nitrox if you have completed the training. Never dive with 100% oxygen unless you are a trained technical diver.

Enriched air or Nitrox carries some dangers in scuba diving.
Enriched air / Nitrox is a great way to dive. However, it does carry a risk of oxygen toxicity which is why you need to be trained to dive with nitrox.

Gas Narcosis

Gas narcosis or nitrogen narcosis is the narcotic effect caused by the gases that you absorb during a deep dive. It is most commonly felt at depths beyond 25 m / 82 ft which is why you need additional training for deeper dives. The narcotic effect when you are ‘narced’ is similar to being drunk, which is why it is also referred to as the Martini Effect. This temporary effect reduces clear thinking, creates overconfidence, and can affect your motor skills. While gas narcosis in itself is not dangerous to our bodies, the risk of impaired judgment can lead to risky behavior underwater.

How to Avoid Gas Narcosis

Not everyone will feel the effects of gas narcosis and it can happen at various depths. Your initial first deep dives should be with a dive professional who can recognize and supervise the effects of narcosis. If you are prone to narcosis, you can avoid deep dives, and if you experience narcosis underwater, you can ascend several meters to alleviate the effects.


Drowning is the most common fatal accident in the diving community. It is usually due to a diver panicking or going unconscious and losing their regulator which is used for breathing. It can also occur if you run out of air while underwater.

How to Avoid Drowning

Always dive with a buddy and ensure that you are both trained with a buddy system. You should feel comfortable before a dive and trained to deal with unexpected situations; such as your mask leaking, a cramp in your leg, a stuck inflator button on your BCD, or in the very unlikely event, what to do in an out-of-air scenario. You should also ensure that you regularly check your pressure gauge during a dive.

Equipment Malfunction

Equipment failure is a common reason for panicking underwater that can lead to fatal consequences. If your dive computer is giving you the wrong no-decompression limits, then you have an increased risk of DCS, and if your pressure gauge is not accurate then you could find yourself out of air underwater. Other equipment malfunctions can occur in your buoyancy control device, your mask, weights, or even fins.

How to Avoid Equipment Malfunction

If you have your own scuba diving equipment, you should maintain and have your equipment serviced by a certified technician regularly. If, like the majority of divers, you use rental equipment then you should check it carefully and speak up if something doesn’t feel right. You should ideally set up your own equipment and definitely check your own equipment prior to every dive. A BWRAF Buddy Check is also important as it allows your buddy to check your equipment while you check theirs too.

Scuba diving equipment on a diving boat.
Always check your own equipment prior to every dive and ensure you conduct a Buddy Check with your buddy!

Ear Barotrauma

Barotrauma caused to the ear occurs when there is a difference in pressure in the middle and outer ear. This is why we need to constantly equalize our ears when we descend under the pressure. If you do not equalize this pressure in your ears it may lead to a perforated eardrum causing pain and loss of hearing.

How to Avoid Ear Barotrauma

Learn how to equalize your ears and sinuses using your preferred method and equalize early and often as your descend. You should also avoid diving if you are congested and cannot equalize.

Read More: Using the Toynbee Maneuver to Equalize

A scuba diving danger is pain caused by ear barotrauma
Learning to equalize is the first step in scuba diving. Equalize early and often to avoid painful ear barotraumas. Photo by Uber Scuba Gili / Unsplash

Pre-existing Health Conditions

Scuba diving exerts a lot of pressure on our bodies. This is why you should maintain a reasonable level of fitness when scuba diving, and be checked by a diving physician prior to beginning to dive. An asthma attack underwater can be fatal, and a injured ankle can lead to an increased risk of DCS.

How to Avoid Health Injuries During a Dive

Do not lie or omit information on your diving medical check. You should be transparent with any previous health issues or injuries. Your diving professional and diving doctor will then make an informed decision on whether you can dive.

Marine Life Injuries

Marine life dangers are perceived to be a bigger threat than they actually are thanks to Hollywood blockbusters scaring us in Jaws or 47 Meters Down. However, most marine life is not aggressive or dangerous to divers and they will avoid a confrontation unless severely provoked. Most marine life accidents happen accidentally with a diver kneeling onto the sand right on top of a piercing sea urchin, or touching a wreck covered in stonefish, or swimming backward into a jellyfish!

How to Avoid Marine Life Injuries

Be conscious of your buoyancy during a dive and never touch any animals, coral, or wrecks. You can find yourself with one less finger if you poke a moray eel, or destroy an anemonefish habitat if you kick their home. If you are participating in a dedicated shark dive, then always dive with a professional and listen to their briefings and respect the rules to ensure a safe and enjoyable dive!

Check Out: The Top 10 Most Dangerous Marine Animals!

The Biggest Dangers Divers Face

Easily, the biggest danger that divers face is impaired judgement.

Impaired judgement can lead you to make mistakes, forget to check your equipment, or take unnecessary risks during a dive.

Alcohol and drugs can lead to this impaired judgement which is why these do not mix with scuba diving. Overconfidence is also another factor that can lead to mistakes.

If you follow the scuba diving rules and respect them then you can minimize the risk of these scuba diving dangers and know how to avoid them.

Happy Bubbles!

Did I include all of the scuba diving dangers that we should be aware of? What other dangers or risks are there, and how can we avoid them? Let me know in the comments below.

Emma was initially terrified of the deep ocean but dived right into scuba diving years ago and hasn't looked back since! After completing her PADI DiveMaster certification and with a Bachelor of Communications (Media) background in film-making, Emma started her scuba career as an Underwater Videographer before becoming a full-time PADI Master Scuba Diver Trainer. She taught and certified hundreds of PADI scuba divers as Open Water Divers, Rescue Divers, Deep Specialty Divers, Dive Masters and more, and then managed several Dive Centres. Her favourite fish (which is also tattooed on her arm) is the Barracuda!