Is Scuba Diving Dangerous? Can You Dive If You Can't Swim?

Before a first dive, people often ask us the same three things: "Is scuba diving dangerous?", "Is it hard?" and "Can I dive if I can't swim?" This guide answers them one by one: the real risks, clearing your ears, health questions, flying after diving, and the ways to start.

The safety facts here come from PADI (a dive training organisation), DAN (Divers Alert Network) and the medical form PADI points to. This is not medical advice. For your own health, always ask a doctor.

Is scuba diving dangerous?

PADI says scuba diving is considered a low-risk activity compared with many other outdoor and sporting activities. The most common medical issues linked to diving are sunburn, seasickness and dehydration, and all of them are preventable.

The risk is not zero. PADI lists the main risks of scuba diving as:

• Ear barotrauma (ear injury from pressure)
• Marine life injuries
• Decompression sickness
• Lung overexpansion injuries
• Drowning

Common causes are not equalising properly, equipment failure, poor dive planning and ascending too quickly. PADI says that in most cases divers can avoid these problems by following correct diving practices, like those taught in the PADI Open Water Diver course. It also says most diving injuries and deaths come from diver error. That is why proper training and following the rules are key.

How training, buddies and checks manage the risk

PADI gives these tips to every diver, from beginners to the most experienced instructors:

• Train before the sea: on the Open Water course you practise skills in a pool, or a pool-like open water site, before you dive in the ocean.
• Check your gear every time: keep it well maintained and do a buddy check before every dive. Fix problems before you get in the water.
• Listen to the briefing: so you know the plan and any local hazards.
• Don't dive alone: a buddy is a partner in safety. If you have an air problem, your buddy carries a spare regulator so you can share air and make a controlled ascent. More in What is an octopus?
• Watch your gauge: PADI compares the pressure gauge to the fuel gauge in a car. Check it often and surface with plenty of air left.
• Don't touch marine life: many creatures can sting on contact or be dangerous when provoked.
• Know your limits: and stay within them.

In our video 7 mistakes new divers should avoid (in Thai), mistake number one is not checking your gear before you get in.

Is scuba diving hard?

PADI says anyone aged 10 or older can learn to dive. You can study the theory online at your own pace, reading, watching videos and taking quizzes. In the water, an instructor teaches you each skill step by step, for example clearing water from your mask.

Feeling nervous is normal, PADI says. Panic underwater is rare when divers are properly trained, but it can happen. Ways to manage anxiety before a dive and stay calm during it are taught on the Open Water course. Controlled breathing, buddy checks and knowing the emergency procedures help divers stay calm. Watch our short on panicking underwater (in Thai).

Can you scuba dive if you can't swim?

PADI says basic swimming skills are required for scuba diving. The Open Water course lists its prerequisites as: able to swim, medically fit for diving and comfortable in the water. During the course, your instructor will ask you to:

• Swim 200 metres without stopping and without aids, or 300 metres with mask, fins and snorkel. Any swimming style is fine, and there is no time limit.
• Float or tread water for 10 minutes without aids.

If you can't swim yet, PADI says you can still try a Discover Scuba Diving experience in a pool. Try breathing underwater in the pool first, learn to swim the distance, then take the Open Water course.

How deep do beginners go?

You don't go deep on day one.

• Discover Scuba Diving: PADI sets a maximum of 6 metres for the pool session and 12 metres for the optional open water dive. It also says you will not go any deeper than you feel comfortable with.
• After Open Water: you can dive to 18 metres with a certified buddy, anywhere in the world.
• Deeper than that: PADI counts dives beyond 18 metres as deep diving, which needs more training such as Advanced Open Water or Deep Diver. It says recreational deep diving usually goes to a maximum of 40 metres. The deeper the dive, the more careful the planning, because of higher pressure, nitrogen narcosis and decompression sickness.

How to equalise your ears

As you go down, the water pressure around you rises, so you need to equalise the pressure in your ears. Divers call it equalising or clearing their ears. PADI says almost every diver has trouble equalising at some point, especially when they start.

• Techniques taught on the course: swallowing, yawning, or gently blowing against a pinched nose (PADI). DAN calls the last one the Valsalva method.
• Start early: DAN advises equalising gently at the surface before you descend, then often during the early part of the descent. Go down feet first, using a descent line to control your speed if there is one.
• Never force it: PADI's most important rule is never to force it or keep descending. If it won't clear, go up a little, a few feet or a metre, and try again. DAN says pain means you descended too fast, and if you can't equalise, end the dive.
• Colds and allergies: DAN says colds, allergies and smoking can make equalising harder. Decongestants can have side effects; take them only if your doctor agrees, and don't use one before a dive if you haven't tried it before.
• When to see a doctor: if you feel ear pain, vertigo or sudden hearing loss during a dive, DAN says end the dive. If the symptoms don't go away, don't dive again and see a doctor.

Do you need a medical check? When to see a doctor

PADI says scuba diving needs a minimum level of health and fitness. Chronic health conditions, some medications or recent surgery may mean you need written approval from a doctor before you dive.

Before you sign up, PADI suggests you read the Diver Medical Participant Questionnaire. It has 10 questions. If you answer no to all of them, you don't need a medical evaluation. If you answer yes to certain ones, you take the form to a doctor, and you need the doctor's approval before the course. The form also says: if you feel ill, don't dive, and if you are pregnant or trying to become pregnant, don't dive.

PADI is clear that instructors and dive shop staff are not doctors and should not be asked for medical advice. Only medical professionals can clear you to dive. If you or your doctor have questions about fitness to dive, you can contact DAN.

How long after diving can you fly?

DAN's provisional guidelines come from a 2002 expert workshop. They apply to air dives followed by flights at cabin altitudes of 2,000 to 8,000 feet, for divers with no symptoms of decompression sickness.

• One no-decompression dive: wait at least 12 hours before you fly.
• Several dives in one day, or several days of diving: wait at least 18 hours.
• Dives that needed decompression stops: DAN says a wait substantially longer than 18 hours appears prudent.

DAN says these guidelines reduce the risk of decompression sickness but do not guarantee you avoid it. Waiting longer reduces the risk further. If you notice signs that may be decompression sickness, get medical advice and don't fly. Plan your trip so your last dive day sits well before your flight home.

Your first dive: try dive or Open Water course?

There are two ways to start:

• Discover Scuba Diving (a try dive): a one-day experience for ages 10 and up. It is not a certification. It starts with a briefing on water pressure, underwater communication, using the gear and safety. Then you practise in a pool or pool-like area, and you can choose to add an easy, shallow open water dive with a PADI professional at your side. Good if you want to find out whether diving is for you.
• Open Water Diver (certification): theory, pool practice, then four open water dives with your instructor. Once certified, you can dive with a certified buddy anywhere in the world, to 18 metres. You don't need to do Discover Scuba Diving first. More on the course in Learn to dive: Open Water.

You don't need your own gear for a first dive. PADI says you can use rental gear from the dive centre, and that owning personal items like a mask, snorkel and fins makes diving more comfortable. More in our scuba gear list.

Want to learn with us? See courses and dates on our dive courses page. Courses are taught by professional instructors from the dealer shops we work with and outside partners. Book and ask questions on LINE at @diverecords.

Before your course day, watch our free video 5 things new divers should know (in Thai) on YouTube.

FAQ

Is scuba diving dangerous?

PADI says scuba diving is considered low-risk compared with many outdoor sports. The main risks are ear barotrauma, marine life injuries, decompression sickness, lung overexpansion injuries and drowning. Most can be avoided with proper training and by following the rules.

Can you scuba dive if you can't swim?

You can try Discover Scuba Diving in a pool. The Open Water course asks you to swim 200 metres without stopping, any stroke and with no time limit (or 300 metres with mask, fins and snorkel), and float or tread water for 10 minutes.

How long after diving can you fly?

DAN recommends at least 12 hours after one no-decompression dive, and at least 18 hours after several dives in a day or several days of diving.

Do I need a doctor's certificate to learn to dive?

Not everyone. Before the course you fill in a 10-question medical form. If you answer no to every question, you don't need a medical evaluation. If you answer yes to certain ones, a doctor has to evaluate you and approve before you dive.