How Does a Snorkel Work Underwater?

If we never step foot in the ocean, we deny ourselves access to over 70% of the world’s wonders.

Swimmers and surfers only see the surface of these immense seas, leaving the kaleidoscopic underwater world for snorkelers and divers to enjoy.

While diving involves a lot of complex equipment and training, almost anyone can enjoy snorkeling.

All you need is a snorkel, mask, and confidence in the water. The snorkel part of your equipment has a tube that extends beyond the water’s surface, allowing you to breathe even when fully immersed.

Snorkels have been around for a lot longer than you might imagine. Long before the first modern-day snorkel was invented, sponge farmers on the island of Crete were using “hollow tubes to allow breathing” while they searched for sponges some 5,000 years ago.

How Does a Snorkel Work Underwater?

At its simplest, a snorkel is a hollow tube that extends above the water’s surface when the wearer’s facing downwards with their face submerged.

The tube transports air to the wearer’s mouth, and nose in the case of a full-face snorkel, enabling them to breathe without removing their faces from the water.

How Does a Snorkel Work Underwater

Snorkels are either separate pieces of equipment or part of a dive or swimming mask. Snorkels are only suitable for surface activities such as swimming when combined with a mask.

Separate snorkels are more versatile and are used for various underwater pursuits, including freediving, spearfishing, and scuba diving.

Snorkels can only provide air if the tip of the tube sticks out above the surface of the water. If submerged, the snorkel tube will fill up with water unless it has a valve at the end to prevent this from happening.

We’ll discuss different types of snorkels and their uses a little later on.

Can You Breathe Underwater With a Snorkel?

As long as the top end of the snorkel tube extends beyond the water’s surface, it will enable you to breathe underwater.

Most snorkel tubes are no longer than 15 inches, so will only allow you to breathe when your face is less than 15 inches underwater.

How Does a Snorkel Work Underwater

Anything longer than 16 inches is considered dangerous because the carbon dioxide you exhale can collect in the tube, preventing air from entering your lungs.

If you dive down into the water, the snorkel tube will no longer have access to air, making it impossible for you to breathe.

How to use a Snorkel and Snorkel Mask?

Breathing underwater with a snorkel is simple enough but takes a bit of getting used to.

The best way to get started is to try out your snorkel and mask in a swimming pool, or where the water’s calm.

Waves can cause your snorkel to fill up with water which, if you’re not used to it, could cause you to panic.

How to use a Snorkel and Snorkel Mask

Getting used to using your equipment in a safe environment first will make your snorkeling adventures less stressful and more enjoyable.

The first thing to do is attach your snorkel to your mask if it isn’t already. You can do this by securing the snorkel keeper or clip to your mask’s strap.

Pull the mask on over your head and make sure it’s comfortable. The mask strap should sit high up on the back of your head, while the snorkel should hang at the same level as your mouth.

Once you’ve got your equipment in place, put the snorkel into your mouth. Your lips should fit comfortably around the rubber mouthpiece, creating a watertight seal.

While you can bite down on the snorkel mouthpiece gently, doing this for extended periods can cause jaw fatigue.

After fitting your mask and snorkel, it’s time to get wet! Gradually place your face into the water, ensuring the top of the snorkel tube remains above the surface. Now breathe.

The first time I tried snorkeling, I found myself holding my breath, somehow not trusting the tube to direct air rather than water into my mouth.

Breathing is crucial, so try to get used to taking slow, deep breaths. This technique will help you conserve energy, meaning you can explore the underwater world for longer once you finally take to the sea.

Once you’ve mastered the slow, steady breaths, it’s time to start moving. Stay in shallow water where you can easily stand up should you start to panic or if water gets into your snorkel tube.

Swim slowly and continue to take deep breaths. As you practice, you’ll start to feel more confident, at which point you can move into deeper water before taking the ultimate plunge into the ocean.

How Does a Snorkel Keep Water Out?

Classic snorkels are very simple, consisting of a tube, mask clip, and mouthpiece.

Also known as wet snorkels, these don’t keep water out, but will quickly fill up if waves engulf them or you dive underwater for a closer look at something.

How Does a Snorkel Keep Water Out

With this type of snorkel, you have to blow into the breathing tube to clear the water before you can start using it to breathe again.

More modern types of snorkels have additional features to prevent water from entering the tube. These include splash guards and float valves.

A splash guard stops water from entering the tube when you’re at the surface, while a float valve seals the tube the moment it becomes fully submerged.

What Happens if you Get Water in Your Snorkel?

If you get water in your snorkel, you need to clear it before you can start using the breathing tube again.

In the sea, waves splash over the top of the tube, causing it to fill with water. When you’re just getting started, it can also be tricky to maintain your position in the water. This may cause you to sink too low, submerging your snorkel underwater.

What Happens if you Get Water in Your Snorkel

More experienced snorkelers are so comfortable with their snorkeling gear that they’ll duck dive under the surface, knowing the tube will fill with water, but confident that they’ll be able to clear it long before it presents a problem.

There are three ways to get water out of your snorkel.

#1 Blast clearing

This is the most popular method of clearing a snorkel. It involves returning to the surface and forcefully blowing air into your breathing tube to expel the water that’s collected there. With traditional snorkels, blast clearing is the only way to get water out.

#2 Purge Valve

Some types of snorkels have purge valves situated close to the mouthpiece. These valves work a bit like bath plugs, allowing all the water to drain away without you needing to do anything more than exhale.

Using a purge valve may leave a little water in the tube, so be careful when taking your next breath.

You can clear a snorkel with a purge valve more completely by lifting your head out of the water and allowing it to drain away naturally.

#3 Displacement Clear

This clearing method is easier than blast clearing and effectively removes water from a snorkel that lacks a purge valve.

To perform a displacement clear:

  1. Swim towards the water’s surface while looking straight up at the sky.
  2. Reach one hand straight towards the surface.
  3. As soon as your hand touches the surface, blow a small amount of air into the tube.

As the tip of your snorkel tube is now lower than the mouthpiece, the air you blow into it will displace the water inside, causing it to exit the tube.

Can You Go Completely Underwater with a Snorkel?

As long as you’re confident about clearing water out of your snorkel, you can go completely underwater with one, you just won’t be able to breathe.

While some free divers can hold their breath for 20 minutes or more, for most of us, a couple of minutes is all we can comfortably manage, so if you want to spend a lot of time diving underwater, snorkeling probably isn’t for you.

Can You Go Completely Underwater with a Snorkel

Using a scuba tank enables you to breathe underwater for up to an hour at a time, making scuba diving a better option for those who love swimming underwater.

Snorkel masks allow you to breathe at the surface of the water, so you can swim or float around with your face submerged, discovering the wonders of the underwater world.

It doesn’t matter what kind of snorkel mask you have, as none offer an underwater air supply unless the tip of the breathing tube is exposed above the surface.

How Long Can You Stay Underwater with a Snorkel?

With the snorkel above the water, you can stay face down indefinitely.

When you go more below the surface, the snorkel offers no breathing advantages, so you can only stay submerged for as long as you can hold your breath. 

The top free divers train for years to perfect the art of breath-hold diving, and the best can stay fully submerged for nearly 25 minutes! 

How Long Can You Stay Underwater with a Snorkel

If you’re new to snorkeling and want to try duck diving and swimming underwater, it’s best only to attempt a couple of minutes at a time. 

Statistics indicate that the average person can hold their breath for between 45 seconds to two minutes, depending on their fitness and training. 

If you want to spend more time exploring deeper coral reefs and marine life without a scuba tank, you must first to improve your cardiovascular fitness and boost your lung capacity. 

Bear in mind that staying completely submerged for longer is easier when the water temperature is warm.

In colder water, your heart will beat faster to maintain your body temperature, forcing you to consume oxygen more quickly. 

Types of Snorkels

There are three types of snorkels to choose from, each of which has its own advantages and disadvantages. 

Types of Snorkels

#1 Dry Snorkels

A dry snorkel is the only type that keeps water from entering the breathing tube when completely submerged.

It has a splash guard that stops water from entering at the top, and a purge valve to make it easier to clear any water that does accidentally enter the snorkel.

In addition to the splash guard, dry snorkels also have a float valve that seals the snorkel, preventing any water from getting in even when it’s completely submerged. 

When submerged the float valve also traps air inside creating additional buoyancy, and making it harder to move around underwater.

This feature makes them unsuitable for activities that involve the wearer spending long periods underwater, such as freediving, spearfishing, or scuba diving.

Dry snorkels are available as both traditional mask and snorkel combinations, and as full-face snorkel masks. 

#2 Semi-Dry Snorkel

Semi-dry snorkels have everything a dry snorkel has except the float valve.

At one end of the tube is a splash guard that prevents water from entering, and at the other is a purge valve that enables you to flush out any water that does sneak in. 

Semi-dry snorkels are the most versatile, but because water can enter the tube more easily than with a dry snorkel, they aren’t ideal for beginners who’ve yet to perfect the art of clearing their breathing tubes.

However, the semi-dry snorkel provides a good balance of comfort and function for scuba diving and free diving.

You can duck dive under the surface without any additional drag or buoyancy and simply clear the water again when you return to the surface. 

#3 Wet Snorkels 

Also known as j tube snorkels, wet snorkels are the simplest of all designs and lack any additional features such as splash guards or purge valves. 

J-style snorkels are basically just hollow tubes, like those used by sponge farmers all those years ago, with a silicone mouthpiece attached. 

Many experienced snorkelers, scuba divers, and free divers prefer wet snorkel masks because they minimize drag and buoyancy, making them more suitable for underwater activities. 

Are Full-Face Snorkel Masks Safe?

Introduced in 2014, the full-face snorkel mask covers your entire face, giving you better visibility and enabling you to breathe through both your nose and mouth.

Many beginners prefer snorkeling with these full-face masks as they can breathe normally without having a cumbersome mouthpiece to worry about.

Are Full-Face Snorkel Masks Safe

A full face mask stops any part of your face from coming into contact with the water, meaning you can smile without accidentally swallowing a mouthful of seawater!

Unfortunately, the design of the full-face snorkel mask makes it impossible to equalize the pressure in your ears as you dive underwater, making it unsuitable for many underwater activities. 

Another problem with the full-face snorkel mask is that it traps the air you exhale.

While this is safe for casual snorkeling in calm water, if you’re having to exert yourself by swimming against the current, you run the risk of rebreathing your own air. 

Heavy or deep breathing in a full snorkel mask could lead to you consuming air that’s high in carbon dioxide and low in oxygen.

Breathing in carbon dioxide can cause dizziness, nausea, and unconsciousness. 

There have even been a few fatalities associated with the use of this style of mask, causing “several bans on full-face snorkel masks.”


Snorkeling is a great way to explore the underwater world without investing in expensive equipment or lengthy training programs. 

With the right equipment and a basic understanding of how snorkeling works, you can enjoy hours in the water, exploring coral reefs, and delighting in the company of sea turtles and other marine life. 


Good quality snorkeling gear is the best way to ensure your safety while exploring the underwater world.

Whether that means a dry full-face snorkel mask or a basic wet snorkel depends on your confidence and experience. 

Your snorkeling experience is only as good as your equipment, which is why choosing the right snorkel for you and your competence level is crucial. 

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