Scuba Diving

The Ultimate Guide!

The ultimate guide to learn scuba diving

Learn all you need to know about Scuba Diving from the experts at

Scuba diving allows you the freedom to explore the beauty and instant serenity of the underwater world, experience the feeling of being weightless, explore beautiful coral formations and see countless species of fish and aquatic animals.

Diving can be a weekend hobby for you, like it is for most of us. We usually meet up with friends early on a Sunday morning, returning with smiles from ear to ear in the afternoon.

Or maybe you’d like to take it further, like some people do, and choose to become a professional scuba diver. One good thing with this career is that you are making a living at doing what you love. A career in diving also allows you to travel to scenic areas and meet many unique people – the perfect job!

No matter how much of a scuba diver you’d like to be, let get you started. We will give you the dynamics of scuba diving in order for you to enter this amazing underwater adventure.

Learn How to Scuba Dive

To learn scuba diving it is not enough to just read this article alone or read other references; it requires proper training from a certified instructor.

There are several diving agencies that offer diving lessons. All of these agencies employ the same diving principles and theories with the only small difference in the standards.

PADI: Professional Association of Diving Instructors

Divers checking Scuba equipment

Quoting its slogan “The Way the World Learns to Dive”, it is the largest diving agency. It offers very simple courses all the way up to becoming a professional diver.

If all you’d like to do is try scuba diving because you just want to get a feel for it, you can enroll in the PADI Discover SCUBA. In this course will be closely accompanied by a professional dive instructor while diving in a shallow and confined area. After this you can continue diving and become a certified diver.

PADI - professional association of diving instructorsPADI offers diver certification from Open Water, Advanced Open Water, Rescue Diver, Divemaster, Master Scuba Diver and five different levels of PADI Dive Instructor. They also offer specialty courses on night diving, photography, Medic First Aid and so much more. PADI support environmental and conservation programs and their banner program on this is Project A.W.A.R.E. – Aquatic Wildlife Awareness Responsibility and Education.

Learn more about PADI at

SSI: Scuba Schools International

SSI - Scuba School internationalThis began from a group of divers who wanted everyone to learn scuba diving. From this it grew worldwide reaching more than 100 countries and is taught in 25 different languages.

Their diver certification programs are very similar to PADI, but it’s often a cheaper alternative. That said, the quality of training does not follow the price, but keeps the same top standard.

Learn more about SSI at

CMAS: Confederation Mondiale des Activities Subaquatiques

CMAS: Confederation Mondiale des Activites SubaquatiquesThis organization is duly recognized by the Olympic Committee and one of the oldest dive training systems.

It also promotes other diving skills as a sport like monofin swimming. Its diver certification program is the same with other agencies, but uses stars to determine certain certification levels. One star means Open Water, two stars is a mix of Advanced and Rescue, and three stars for Divemaster. These stars are colored red. Blue stars represent different instructor levels.

Learn more about CMAS at

The difference between scuba diving and snorkeling

The difference between Diving and Snorkeling Snorkling and scuba diving

First let’s start with snorkeling and skin diving  as most people think it’s the same sport.

  • Both include the mask, fins and snorkel.
  • Both practitioners spend most of the time in the surface, looking down at the world below.

The snorkelers will stay and enjoy the sights from the surface, whereas the skin divers will stay at the surface to get an overview of what’s down under the water. Skin divers swim down holding their breath and spend as much time as possible at the shallow reef.

Scuba divers don’t resurface for air, like skin divers, but bring down air to breathe in the tanks. Therefore they need additional equipment and more training. What to get better at snorkeling? Here's our Full Snorkel Guide.


So which one is the best: Snorkeling, skin diving or scuba diving?

It’s all comes down to what a person prefers. Some people like the overview you get from the surface as a snorkeler, but some like the fact that they can spend more time underwater with scuba gear and close in better under the water. Skin divers get both the overview and the close up, the only drawback being that they have to resurface. Jon Milnes

Diving and Snorkling Equipment

We can generally classify two kinds of diving equipment categories based on their usage and function, the snorkeling and SCUBA equipment. Read the Full Guide to Snorkel Gear. As a scuba diver you’ll be introduced to a lot of new dive equipment. An essential piece of SCUBA equipment is the tank that holds the air you breathe on your dive.

You’ll also need a regulator set, consisting of a regulator mouthpiece and a first stage, which is attached to the tank. In addition, there is a pressure gauge, which lets know how much air you have in your tank, and an alternative regulator, just in case you or your buddy needs a spare regulator.

Snorkeling Equipment

Snorkeling equipment is generally used on the surface and in certain depths of water. This is a pre-requisite gadget before SCUBA gear. It is highly suggested to start with snorkeling equipment because if you have to buy your own, this type of gear will fit your budget and it’s important that it fits comfortable.

Scuba Mask

Female scuba diver with scuba mask

Jon Milnes

If you want to be able to see everything clearly you will need a mask because what your naked eyes can see is limited. A mask creates a dry space, which helps your eyes to focus. The lens of the mask should be made out of tempered glass.

You also want to make sure that the mask fits correctly and comfortably. The contours of the human face can vary considerably from person to person, so it is important that you try your mask on before going in the water. Simply hold the mask in place without putting on the strap and gently inhale. Hold your breath for a few seconds then look down and wiggle your head sideways. If the mask does not fall off, it fits you. If it does fall, choose a different one. Keep testing the fit of each mask you try on until you find one right for your face.

Another feature a mask should have is a nose pocket. There are instances when your mask gets fogged or water leaks in. The only remedy for this is an underwater skill called mask clearing. You simply let the water inside your mask drain out by exhaling through your nose. As air goes out of your mask, so does the water. This is the main reason you cannot use goggles in scuba diving because it’s not possible to clear when it’s flooded except to surface up. Also, a nose pocket allows the pinching of your nose during equalization.

Most of the masks today are low profile, which means less air is needed when clearing if it floods and also provides a wider field of vision. Some recent models have an optional feature of a one-way purge valve for easier water clearing.Mask for diving

As with any piece of snorkeling and scuba equipment after a dive, make sure to rinse your mask with fresh water to get rid of the salt because this can cause corrosion or damage to the material. Even after diving in fresh water like a swimming pool the mask still should rinsed to wash away any chlorine or other chemicals.

Read more: What to Look for When Buying a Mask

Please remember: Protect and preserve your diving equipment by never allowing your diving equipment to dry in the sun. Instead, hang it up in the shade and then store it in a dry place.

Snorkel for scuba diving

Scuba SnorkelThis piece of standard scuba diving equipment allows a diver to breathe only at the surface. It is nothing but a plastic tube not longer than 43 cm (17 inches) with a large bore opening and a mouthpiece on the other end.

With all your scuba gear on, it lets you breath at the surface without using your regulator, which maximizes air consumption. In some instances at surface when the water is choppy or when you are low on air, a snorkel may allow you to breath while facing down in the water, making breathing easier and making you more relaxed.

Features of a snorkel may include fitting the contours of the side of your head, which reduces resistance. It may also include smooth rounded bends to lessen resistance to breathing and some may have a purge valve.

One feature a snorkel should also have is a brightly colored tip so that you will be seen more easily at the surface. Since a snorkel is attached to the side strap of the mask using a snorkel keeper, it is important to note that the proper position is always at the left side. You don’t want your snorkel to get tangled up with your regulator, which comes from your right side.

Read more: Dive Gear: When to Buy What?


Torben Lonne -

Our feet are not webbed like frogs or ducks so fins assist divers’ motion under the water by providing a large surface area for kicking. Fins have pockets for your feet to be put into and blades that help with propulsion.

There are basically two types of fins: An Open heel type that has adjustable straps and full-foot fins that enclose your feet. Most of the divers today use the open heel type because they come with the use of booties, which protects your feet when you walk into the water.

There are some points to consider when choosing what kind of fins you will be using, but above all, comfort and fit comes first. Diving in calm and clear tropical waters may only require flexible full-foot fins. But diving in an area with strong water currents may require you to use fins with longer blades. Cave diving may require fins with shorter blades, which minimizes the ground disturbance. Various finning techniques may require certain types and designs of fins. The most common and strongest finning technique is the flutter kick, which is done by moving your legs in a vertical direction.

Read more at Choosing Scuba fins: a basic guide

Exposure suits

Try Dive Equipment in the store

Dario Sabljak

The surrounding water temperature of your diving environment is colder than your body temperature. The tendency is you will lose body heat and that is why you wear exposure suits to prevent this from happening.

Wet suits, usually made from neoprene rubber, are used in tropical diving areas. Thickness of the material may also vary and mostly available in the market today range from 0.5 to 8 mm. But in some areas where the water is very cold, dry suits are worn. A diver’s body is dry by creating an air space inside the suit supplied from your tank. This prevents body heat loss, which could lead to hypothermia. Keep in mind - using a dry suit requires special training before you go diving.

Read more at Dive Gear: When to Buy What?

Scuba Equipment

This gear is used by divers, together with the snorkeling equipment, to go underwater.

Buoyancy Control Device (BCD)

BCD: Buoyancy Control DeviceIn order for a scuba tank to be easily carried underwater it needs to be held in place. BCDs can be worn like a jacket, using a backplate to which the tank is firmly attached at the back.

BCDs have rubber bladders inside that can be inflated or deflated to regulate a diver’s buoyancy. They also have a low-pressure inflator mechanism, which is attached to the regulator. By supplying air from the tank via the regulator, you can inflate your BCD or do it manually by blowing air from your lungs. Don’t worry if you put in too much air, the bladder will not explode. An overpressure relief valve is an important feature of a BCD, which lets excess air to escape.

Unlike other scuba equipment, a BCD demands extra rinsing for it to last. Rinse it by pressing the inflator button and allow freshwater to enter the bladder half-filled. Then fully inflate it manually and shake it. In this way, the saltwater that entered the bladder will be dissipated.

Scuba tanks

Tanks getting filled


Unless your source of breathing air is surface supplied, you need a container full of air to enjoy diving. Scuba tanks are metal cylinders made up of either steel or aluminum that are designed to contain high-pressure air. Scuba tanks are filled with compressed air using an air compressor made for scuba tanks.

Tanks may vary in size depending on their capacity and pressure ratings. The most common sizes used by dive shops are 10 liters / 72 cubic feet and 12 liters / 80 cubic feet.

For a tank to be sealed and supply air to the regulator, a tank valve is an essential component. Older valve versions are the J-valves, which have a reserve valve whenever the air gets low at 50 bar / 500 psi. Today the most commonly used types are the K-valves, which are a simple on and off valve. The DIN system, generally used in Europe, can withstand high working pressure. The DIN system screws into the tank. There is also a Yoke-valve that screws around the tank valve, which is the most common system. Regardless of tank type, all systems have an O-ring that seals when the regulator is attached.

Tanks should only be filled at accredited airfill stations and most tanks are filled up to 200 bars / 3,000 psi of pressure.  Typically, most tanks have their pressure ratings engraved on the top part of the tank just below the valve. Along with this are engraved markings of the concerned government agency regulating its usage, type of material, name of manufacturer and serial number.

Tanks should also undergo a periodic test to determine if it is still safe for usage. A tank should be visually inspected for corrosion and other contaminants one time per year. A hydrotest should be done once every five years to determine whether the material is still fitted for high-pressure air; certified technicians should do all tests and the test dates should also be marked on the tank.

Please remember: Some specially marked tanks are designed only for mixed gases and require specific standards. This may require a special training course for you to use it. An example of this is Nitrox and Trimix used for technical diving. IF YOU ARE NOT A CERTIFIED NITROX OR TRIMIX DIVER, DO NOT USE THIS KIND OF TANK!

Something to consider regarding tanks is if you want to own your tank or just rent one. This all depends on your need, the availability of supply and servicing facilities and frequency of diving, among other things. Most people diving while on vacation just rent, whereas if you dive at home most divers buy their own.


Scuba RegulatorsA Scuba tank holds high air pressure, so the only way to breathe the air is through a regulator, which controls the flow of air. The first stage regulator is connected to the tank valve reduces air pressure to an intermediate flow of 10 bar / 150 psito the second stage regulator which gives you a pressure comfortable for breathing. A low-pressure hose connects the first and second stage regulator.

Today, most regulators have demand valves, giving air only when you inhale. And as discussed above in the snorkel section, regulators must be used on the right side to avoid entanglement with the snorkel.

Functioning like a gas meter, regulators are also equipped with a submersible pressure gauge (SPG). This measures the actual tank pressure. Of all the pressure hoses in the regulator, SPG is connected to the first stage regulator through a high-pressure hose.

Regulators also have an inflator hose that will be attached to the BCD for inflation. This is connected from the first stage regulator through a low-pressure hose.

There are two separate second stage regulators. The black colored regulator, which has a black hose, is the primary regulator and is the one you will be using. The other, which is usually yellow colored, including its hose, is called an alternate air source, also called an octopus. This is a back-up regulator and used when your buddy is low on air or runs out of air and needs to share air.

Please remember: Make sure that the dust cap is in place while rinsing with fresh water after a dive so that the water will not enter the first stage. This will prevent damage and corrosion.

Weight system

Diving weights


Your body has air spaces in addition to the spaces created from your equipment, which makes a diver float or positively buoyant. For a diver to descent, this is compensated using lead weights.

If you are using a weight belt, make sure that it can easily be released using your right hand and not securely fastened. Divers use the term quick right hand release. This is a standard set-up in gearing up so that you can easily get rid of your weights in case of an emergency. Also make sure that the lead weights are placed at the side of the belt and not at the back where it will tend to bang against the tank, which not only makes an annoying sound.

Weight systems can also be integrated with the Buoyancy Control Device placed at the side in specially designed rigid pockets. But the same principle of quick release is still employed and can be easily ditched in case of emergency.

Safety Equipment

This equipment is not part of the main scuba equipment, but these accessories are a big part in preventing surface and underwater situations that could possibly lead to accidents.

Here are 5 pieces of equipment to improve your safety while diving.

Dive Knife

Diver knife and safe marker


This is used during situations like entanglement or other matters where you need a safety tool. A Dive knife is made of stainless steel or Titanium and encased with a plastic case. It can be attached to the leg or BCD or easy handling. And as all divers know: It’s a tool; not a weapon!

Surface Marker Buoy (SMB)

Deploying your DSMB

Katrine Overbeck -

It’s difficult for someone at the surface to locate where you are once you are underwater. Only exhaled bubbles indicate a diver is underwater and these are usually difficult to see. For ease of usage and to avoid entanglement, SMBs are connected with strings through a reel or spool.

SMBs provide a diver surface markings to alert people on the surface of your presence. This is relatively helpful during ascent and when you are about to finish your dive especially for passing boats; once SMB is floated at the surface, they will be warned not to come near the buoy since divers are just beneath.

Read more: Learn how to deploy an SMB


If a diver needs to get the attention of the surface crew, a whistle will come handy especially if you are boat diving. Further, it helps signal for help in case of distress and emergencies. Some whistle or horns are attached to the inflator hose that creates a loud noise both at the surface and under the water.

Underwater lights

Diver over using dive light

Vittorio Bruno

Most dives are done during daytime hours, but some dives we do during dawn and dusk where the underwater night animals come out for food. However, bring an underwater flashlight even if it is just a daytime dive. Not only will this give you a source of light underwater but also marks your presence once you ascend and finish the dive.

Diver Computer

Most divers wear a dive computer to monitor their bottom time. Modern computers are monitors your bottom time, depth, surface interval and much more. So if you do not want to manually calculate your dive profile using the dive tables, buy a dive computer.

Scuba Diving information

Before you can fully explore under the water, you need to take lessons from a dive instructor sanctioned by a diving agency. In this way, you will get a certification that will categorize your diving skills and limitations.

By taking the Open Water Scuba Diver course, you will be taught the basics of scuba diving, practice your diving skills in confined water and do an actual open water dive. Although diving agencies may vary, this level limits divers to go down to no more than 18 meters (60 feet).

Guaranteed you will want a higher certification, as you will want to learn more diving skills. In the Advance Open Water Scuba Diver course, specialty skills will be taught on deep diving up to 30 meters (100 feet), multi-level, Peak Performance Buoyancy and underwater navigation.

As you acquire more experience, you may feel the need to know the skills on how to respond to situations like injuries and accidents. That’s when enrolling in the Rescue Diver course will be essential. You will be taught to calmly respond to certain diving emergencies both in surface and underwater, ranging from a simple situation to an unconscious diver.

Getting this far with diving is already an achievement, so why not make diving your professional career? Divemaster is the first level for professional diving. For this you will be taught how to assist during diving lessons and handle small groups as dive guide.

Then fulfill all your dreams and become a Master Scuba Diver. This is the highest possible non-professional certification level that can be attained for recreational scuba diving.

At this level and loads of experience, you may want to share your knowledge in diving by becoming a Dive Instructor. After successfully passing the Instructors Development Course and Instructors Examination, you will be able to certify divers from Open Water to Divemaster. Further instructorship has various levels of specialty certifications and may vary between diving agencies.

The ultimate achievement in diving certification is becoming a Course Director. You may not only teach all dive certification courses, but you may also help in the management and dynamics of your diving agency.

Diving as a means of Travel and Vacation

There are a number of reasons why we travel on a vacation and diving could be one of the reasons. Where you travel or go for vacation will depend on areas you haven’t been, but you may also search the web for destinations best for diving. Check out our top 10 world destinations.

It is best for you to book your diving holidays in advance, making your choice of destination, airline, hotel and dive shop reservations(choosing a dive center). It is also suggested that you go in groups and have a group booking/reservation. Not only will you share your diving vacation with your close friends, but you also cut expenses doing this. And for times when you need to bring your scuba gear, leave your tanks and weights at home. Some airline companies offer promotional upgrades for scuba divers, giving special mileage cards and extended baggage limits for scuba equipment.

While traveling you get to experience the best of diving. Swimming past a beautiful reef with amazing life around you is the best feeling. Big marine life is so exciting, getting the chance to see hammerheads, great whites, whale sharks, Mantas, groupers, barracudas, nudies, octopuses or anything else on your bucket list.

Remember to check the normal diving season of your dive destination and do not make a reservation during monsoon and typhoon season. Also, do not be tempted to take special discounted low rates during this bad weather season. This might be okay for a non-diving vacation, but if you are planning on going diving you need the weather to be good because it’s no fun spending your dive vacation in your hotel room.

Please Remember:  Do a final check before travelling, making sure that you have everything you need for the trip. If you are bringing any dive equipment, check that you have everything and it is packed securely. Check all documents and remember your sunscreen lotion!

Scuba Diving on a Liveaboard

If your budget permits, consider going on a liveaboards trip because this is one of the best ways to experience scuba diving. If some vacationers choose a luxury cruise to relax, live aboard is its counterpart in diving. Usually onboard a vessel that is equipped with comfortable accommodations, sumptuous meals and excellent diving services, all you need to do is make a reservation, pack your stuff and go onboard.

Read more about the liveaboard way.

On a dive liveaboard, you will be doing nothing but diving and living aboard a boat with other divers and you will be taken to different dive locations every day. It’s great to wake up at and be able to just jump in for a morning dive at a new dive spot each morning.

History of Diving

Long before our parents and grandparents were born, people have been exploring the marine environment for food. People started out by holding their breath, but this only allowed only a few minutes time under the water. Some created containers that held air by stitching animal skin or leather, which trapped air, giving them more time underwater.

The first man ever recorded diving dates back to 820 B.C. Preserved in the British Museum is a sketch of a diving man breathing underwater from a bag made out of stitched sheepskin. They say it is a Mesopotamian soldier who is attacking their enemies from underwater. This actual sketch is now the logo of ADSI, one of the diving agencies.

From that time on, more inventions were made to improve diving. Allegedly in 320 B.C., Alexander the Great used a huge bell allowing him to go underwater while breathing from trapped air inside the bell. This marks the first model of a diving bell.

An Englishman in 1720 was successful in collecting seashells that were located 20 meters below the water. He made a hopper of wood that fit only one person. This was the first model of a submarine.

In the late 1800’s, the helmet system was born. This system was given air from the surface using an air pump. This first diving helmet led to what is popularly used today in underwater salvage works.

In the 20th century, the Japanese invented the Ohgushi. This is basically a diving mask that is supplied with air from the surface using a pump. This was proven to be effective when they used it in the gathering gold bars that sunk with the vessel Yasamaru in 1924.

Ever hear of Jacques –Yves Cousteau? You definitely are a diver if you have. Cousteau was a Frenchman who started out as a gunnery officer in the French Navy.  However, his naval career was cut short by a car accident in 1930. Despite this, his passion and love for the ocean continued to inspire him, which eventually landed him as a seasoned oceanographer.

Cousteau teamed up with a friend of his by the name of Emile Gagnan who happened to be an engineer and an ocean enthusiast. The two of them wanted to gain some freedom, being able to explore the underwater environment without all the hoses coming from the surface. In 1945, they successfully invented and perfected the open-circuit SCUBA system, and thus the acronym Self-Contained Underwater Breathing Apparatus. This invention became viral especially in Europe and the United States. They called it the Aqua-Lung, which gave way to the development of modern scuba equipment.

Dangers in Scuba Diving

The first thing, when talking about diving, that gets into mind is adventure, fun and excitement, but there are dangers that go with it. However as the science of diving evolves, these risk can easily be prevented and avoided by following and observing diving rules.


Once a diver is underwater, the body’s air spaces, especially in the middle ear, are exposed to increasing pressure and this increases as a diver goes deeper. You need to remember that pressure is increased by 1 atmosphere every 10 meters deep. But divers easily adjust to this by pinching their nose closed while blowing air, yawning their jaws sideways or just by swallowing saliva. This is called equalization.

When does this become a danger?

Sometimes before a dive, a diver may have a cough or a cold that causes phlegm to block the sinuses and airways. When a diver neglects this and goes underwater, he/she will have a problem doing equalization as the airways are already blocked. Pain may occur in the ear as the increasing pressure is not equalized and this is worsened when a diver exerts a lot of force or effort to equalize, which can cause the ear to rupture.

Preventing this

When you are on a diving vacation and suddenly you get a cough or cold, you may take medicine but make sure to take it at least one hour before the dive. If you have severe cough and cold, you can still take medicine but do not go diving. Get some rest instead and take time to recover as there will be other days to dive.

Decompression Sickness

The air divers use in their tanks is simply compressed air containing 28% oxygen, 70% nitrogen and 2% other gases. Normally our bodies only use oxygen, and the other gases are expelled outside the body’s system. But as we go diving, nitrogen, which has a greater percentage composition than other gases and is not consumed by our body, is being absorbed in our body tissues due to water pressure. So the deeper you go, the more nitrogen your body accumulates. Read more:

When does this become a danger?

When a diver is starting to ascend, the water pressure is decreasing. However, when a diver ascends too fast, the nitrogen accumulated in the body tissues will form bubbles usually at the joints, causing a diver to bend his/her arms because of pain. This is the reason why decompression sickness is also called the bends.

Preventing this

Remember to dive within your limits. Divers are may be required to have specialty and advance trainings before exploring deeper areas. Based on what your certification level is, always make a dive plan mapping out your maximum depth for the dive and how long you plan to stay at that depth. Make sure that your dive plan is reflected from the Recreational Dive Planner or simply called the Dive Table where a certain time is allowed in a certain depth. Following these time and depth limitations will prevent too much accumulation of nitrogen in your body system.

The bends occur when a diver ascends too fast. That is why the normal ascent rate is set at 60 feet per minute or 1 foot per second. Anything faster than that is relatively dangerous. So during ascent when you are about to finish the dive, instead of going straight up towards the surface, slowly swim horizontally at 45 degrees while you enjoy the underwater scenery. This is further relieved by doing a safety stop at 15 feet for 3 minutes, which has become a mandatory practice before a diver surfaces out of the water.

Worst case scenario where a diver is already bent, immediately contact the nearest recompression chamber. This is where the diver will be placed inside a metal chamber together with a hyperbaric doctor. Treatment involves the diver being subjected to the same pressure in the actual dive and slowly releasing the pressure as this may deplete the nitrogen bubbles embedded in his/her tissues.

Lung Expansion Injury

On land our lungs continuously expand and contract as air goes in, supplying much needed oxygen. This is also the same under the water except that is now subjected to pressure. During diving, our lungs are comparable to a balloon that is contracted when you go deeper because of pressure; biologically this is relieved by constant breathing.

When does this become a danger?

When a diver rapidly ascends to a shallower area or even directly straight up to the surface, his/her lungs (acting like a balloon) can no longer hold the sudden change of pressure causing it to burst, which is often fatal.

Preventing this

Lungs, like a balloon, will only burst if pressure cannot escape. This happens in diving when we hold our breath. So just remember the golden rule in diving: “Never hold your breath, and breathe continuously”. In a very rare occasion when you run out of air and you need to directly go the surface, just make an “AAAHHH” sound, letting the air pressure in your lungs go out during this prolonged exhalation, which will prevent expansion.

Oxygen Toxicity

Oxygen becomes toxic beyond 140 feet deep and this is the reason why the maximum depth at the dive table is set at this depth. An early sign of oxygen toxicity is nausea and eventually progresses into loss of consciousness and sometimes death.

When does this become a danger?

Oxygen toxicity will definitely set in, as well as other diving related sicknesses, if you go beyond the limits set by the dive table.

Preventing this

If you plan your dive properly based on the standards set by the dive tables, oxygen toxicity will not occur. In some instances, especially in work-related diving activities where you need an extended time underwater or perhaps you need to go deeper, certain gas mixtures can be introduced. But a diver should undergo proper training by a certified instructor and the actual mixing of gases should only be done by certified personnel in a certified facility. The more popular gas mixtures are Nitrox and Trimix.

Marine Animal Injury

When you are diving, especially in a healthy coral reef area, you will encounter a variety of sea creatures that are very beautiful and are typically the subject of macro-photography. But you must be careful because most of these creatures have stinging cells that release toxins that are usually very painful and sometimes causes death if you come in contact with them. The box jellyfish and the Portugese man-of-war have nematocysts which cause a burning sensation. Stingrays are equipped with a harpoon-like structure at their tails that whip when stepped on or provoked and cone shells have  powerful neurotoxins that can easily knock a diver down.

When does this become a danger?

Normally, all marine stingers are not aggressive and will only strike a diver if and when they are provoked.

Preventing this

Never touch anything underwater; as the saying goes, “Leave only bubbles, take only pictures”.  In addition, maintaining neutral buoyancy will also prevent this as most of these stinging creatures are at the bottom of the sea floor.

Today, diving is relatively safe. In fact, based on surveys, there are more accidents in many other sporting and leisure activities compared to diving.

Go Professional and Experience the Best of Diving

Divemaster is the first level of professional diving. It allows you to assist in scuba lessons and serve as a dive guide. Once you’re a divemaster, you may get the urge to want to teach diving to others. So the answer to this is instructorship. But again, there’s a lot more in diving.

If teaching diving doesn’t interest you, but you have the passion for photography, then underwater photography is the thing for you. Or maybe you are into underwater cave diving or going deep with technical diving. And if you love to dive and also love to write, we’d love for you to share your diving experiences with us and become a writer for because

There’s something for everyone in diving!!!

Torben Lonne Written by TORBEN LONNE

Torben is a top skilled PADI MSDT instructor. He has worked several years with scuba diving in Indonesia and Thailand – and dived most of his life.

He is also the co-founder and chief-editor of

Follow Torben on Google+ or Twitter

More articles by Torben Lonne

Discus Scuba Diving & Ask questions you might have

Scuba Diving – The Ultimate Guide!
5 (99.05%) 169 votes

Leave a comment below if you have questions, think we left something out, made an error or want to say something about Scuba Diving. We are happy to answer any scuba related questions!


  1. Michael Kjeldsen

    AWEsome article!

    I have a question regarding where to get a certificate:

    I’ve always had the impression that PADI is the most expensive option, and I’m considering other agencies.

    Who would you recommend? I’ll mostly be diving in Scandinavia.

    Keep up the great work :-)

    • Torben Lonne

      Thanks, Michael. I really appreciate it!

      I wouldn’t say PADI is expensive for a scuba course, but it all depends on in which country you are. PADI is often the easiest choice on a holiday destination because you always know what you get.

      For a cheaper dive course you could consider CMAS, they are very strongly represented in Scandinavia, and most often as a dive club which keeps the costs down.
      I’m not sure how they are in other parts of the world but I know for a fact that they are very active in Denmark and many courses and trips are done in the weekends as a club activity. This was how I started diving, and I really got a thorough CMAS */open water course.

      But as with any dive training is all about who is teaching you. Whether it’s PADI, SSI, CMAS or any of the others, the Instructor is responsible for your training and the quality. Before booking any course, always talk with your instructor and make sure you are a good match, and she’s the type you would like teaching you.

      Hope this was helpful!

  2. David Tombs

    I was trained originally by BSAC, but have a variety of qualifications from other agencies. Clearly the quality of instructor rather than the agency is possibly the most important factor when learning to dive safely. However, you need to learn or gain experience in the kind of conditions in which you are going to dive, with an experienced buddy or guide.

    • Torben Lonne

      I could not agree more! Conditions is an important factor in learning scuba diving. An it is the problem with “vacation” certifications, if you want to dive at home, as you need experience in those conditions. It can easily be solved by hiring a local guide to get you tuned in to the local diving, or find a buddy with a lot of experience in the local area. Usually this is where the dive clubs comes in handy, as well.
      Thanks David!

  3. Micki

    Simply wish to say your article is as astonishing.
    Thanks a lot

  4. Ron Anderson

    Approximately how many people have accumulated 500 hours of scuba diving? Approximately how many people have accumulated 500 dives?

    • Torben Lonne

      Hard if not impossible to say. It’s possible to know how many there’s certified, but beyond that is not possible.

  5. Debbie Reno

    This may be an incredibly stupid qiestion,yet I have to ask. Can someone that uses oxygen all the time scuba dive or snorkel? My thinking is since divers use oxygen to dive that someone on oxygen just may be able to participate. Thanks for your time.


Leave a reply

Your email address will not be published. Required fields are marked *

Pin It on Pinterest

Share This