Scuba Diving Terms - A Dummies Guide

Learn all the lingo to talk like a seasoned scuba diver

Scuba means Self Contained Underwater Breathing Apparatus

Frans Daniels

Scuba-diving, like many activities seems to have a language all of its own, with confusing concepts, technical terminology and an ocean of jargon to decipher.

To help newcomers break through this barrier we've developed a dummies guide to scuba diving, so that you can get to grips with what divers are talking about. Find out what SCUBA stands for, what PADI is, what it is to be narked, and so much more.

After reading our guide, you may even feel confident enough to talk the talk yourself...

Love marine life?

Basic scuba diving terms

SCUBA

S.C.U.B.A is actually an acronym. It stands for Self Contained Underwater Breathing Apparatus. Basically speaking, it is the name for the gear you need to breathe underwater. So Scuba diving means to dive using scuba equipment.

PADI

If you’ve visited a dive center or been exposed to the diving world at all, chances are you’ve come across this term. It’s everywhere, but what is PADI? PADI is an acronym. It stands for the Professional Association of Diving Instructors. It is the world’s largest dive certification organization and many divers have taken their courses, from the Discover Scuba Diving course right up to Rescue Diver and above.

PADI is not the only dive certification organization by any means. You may also come across SSI, CMAS, NAUI, BSAC, TDI and more.

Open Water Diver

Open Water Diver is the common name for a diver who has their first certificate in scuba diving. The Open Water Certification means that a diver is competent in the water and is qualified to go on a scuba dive with a dive guide or a buddy.

Buoyancy

Buoyancy is the term used by divers to describe how they float in the water. A good diver will be neutrally buoyant, meaning they can hover motionless in mid-water. If a diver sinks to the bottom, he or she is negatively buoyant. If they rise to the surface, they are positively buoyant.

Viz

You will often hear divers talking about Viz. It means visibility, or how clear the sea is and how far you can see underwater. Normally, divers refer to viz as either 'good viz' or 'bad viz'.

Buddy

Your buddy is your faithful friend & partner for a scuba dive. Divers always dive in pairs for safety and your buddy will help make sure your equipment is in order & keep an eye on you during your dive in case you have any problems. If you are a good buddy, then you will do the same for them in return.

Laya Clode

Your diving kit

Tara North

Tank

Not a heavily armoured vehicle on tracks, but the container on your back containing the air you breath on a scuba dive. Sometimes this is called a bottle, especially by Australians.

BCD

Your BCD, or Buoyancy Control Device, is the jacket you wear when you go scuba diving. You can put air into your BCD and also remove it to control your buoyancy while underwater and on the surface. A crucial piece of kit! BCD’s also have handy pockets and d-rings to store all sorts of bits and bobs that might come in useful on a dive.

Regulator

Your regulator is another crucial piece of kit. It delivers air from your tank to your lungs at a suitable pressure to breathe. There are various parts to a regulator. You may hear divers talking about their first stage or their second stage. These are both different parts of a regulator.

You may also hear divers talking about their ‘occy’ or octopus. They are not, as you may first assume, talking about an incredible marine animal they have befriended or keep as a pet. Your octopus is another part of your regulator, more formally known as an Alternate Air Source. It is a back-up source of air in case of emergencies.

Fins

Your fins transform you from mere a human into mermaid-eque underwater being, albeit temporarily. They attach to your feet, making it almost impossible to look elegant on land, but ensuring you can propel yourself through the water with consummate ease.

There are essentially two types of fin. A full foot fin is worn rather like a shoe and is the most simple type of fin. Many divers, especially when they get a little more experience, prefer an open heel fin. This type of fin is worn with a neoprene boot and attaches to the foot with a strap. People who are not divers tend to refer to fins as flippers. That’s cool with us.

Booties

Many divers may dream of finding underwater treasure from a long long pirate ship. That’s unlikely to be what your dive buddy is referring to if they enquire about your bootie however. Your booties are simply neoprene shoes or boots - used in conjunction with open heel fins - to ensure comfort, warmth, and a secure attachment to your fin.

Weights

With a tank of air on your back and a wetsuit keeping you snug and warm, you are remarkably buoyant and floaty. In order to get underwater, you’ll need a little extra weight. These weights are either attached to a weight belt which is worn around your waist, or placed in specially designed quick-release pockets on some BCDs - known as integrated weights.

Depending on where you are in the world, they are measured in kilograms or pounds. So, if you hear someone asking how many kilos’s? or how many pounds?, they are not being rude. They are asking if you know how much weight you require for your scuba diving set-up.

Wetsuit

Wetsuits aren’t exclusive to diving, so no doubt you are familiar with a wetsuit already. They are neoprene body suits providing warmth and protection. They are especially crucial for diving however as your body loses heat more quickly underwater. In fact, most people lose heat about 20 times faster in water than in air.

If you are diving somewhere very warm, you may be offered a shorty. This is a wetsuit with short arums and sleeves. Wetsuits also come in different thicknesses. Often, in the tropics a three millimeter thick wetsuit (a three-mil) is fine. For colder water, five and seven millimeter wetsuits are preferred. For really cold waters, you also get dry suits.

Mask

Our eyes are not designed to see underwater unfortunately. We need a little air in front of our eyes to allow them to focus. This is where your scuba diving mask comes in. It creates an air-pocket in front of your eyes so you can take in all that is wonderful while underwater. Crucially, a scuba diving mask also covers your nose to allow you to equalise the air pressure in your mask as you go underwater. Don’t ever try to go on a dive with swimming goggles - your eyes will pop!

Snorkel

Snorkel’s attach to the side of a mask. They are a very simple tube which allows you to breath air while on the surface, but with your face in the water. For scuba divers, they act as an additional safety feature.

Technical jargon

Equalise

When you go on a dive, or underwater to any depth of note, you experience an increase in pressure. You will feel this effect in your sinuses & inner ear, which need to be equalised by breathing out through your nose while pinching it shut. You often experience the same effect when an aeroplane is coming in to land.

Bar

Bar is the measurement telling you how much air is left in your tank, as well as a place to have a drink with your friends. It refers to the amount of pressure the air is under. Generally, you will start a scuba dive with 200 bar in the tank. If your tank has 100 bar left, it means there is half as much air inside. In the US, they often use a measurement called PSI instead of bar. 3300 PSI is the same as 200 bar.

Narcosis

An effect caused when divers go a little too deep and breathe nitrogen in higher concentrations. The feeling for many is a little like being drunk, where they suffer from a lack of coordination, a misplaced feeling of security and are prone to doing slightly silly things. Many people refer to it as being 'narked'. If you ever feel narked on a dive, come a little shallower. It is not a good idea to feel drunk when you are quite a long way underwater.

Safety Stop

When you go diving, the water puts your body under pressure. Put very simply, before you surface from a scuba dive, you need to decompress your body. This means ascending very slowly and taking a 3 minute safety stop in shallow water before coming back to the surface.

You may also hear divers refer to their safety sausage, SMB, or Surface Marker Buoy. This is in an inflatable tube that allows a divers location to be clearly seen from the surface.

Deco

Deco is a common term among divers that stands for decompression limit. It usually refers to the maximum amount of time a diver can stay at a depth before he needs to come shallower. You may hear a diver say they had come shallower as they were getting close to 'deco'. This means that their dive computer was telling them they had to return to a shallower depth to stay safe.

Nitrox

Nitrox is a mix of gas that divers often use to go scuba diving instead of air. It has increased levels of oxygen, which means divers can dive for longer before they reach 'deco', or their decompression limit. Tanks containing nitrox instead of normal air are have bright green & yellow labels to tell them apart.

No Fly Time

Being underwater can feel a little like flying. The feeling of weightlessness is something truly wonderful. When divers talk about no fly time though, they are referring to an amount of time a diver must spend back on land before it is safe to take to the air in a plane. This is due to the gasses that accumulate in your body when you dive.