A snorkel is the simplest thing in a dive bag and the one people put the least thought into, which is why so many divers end up with a jaw ache after twenty minutes and a mouthful of water every time a wave passes. The differences between models are small but they all land in the same place: how much water gets in, how easily you can get it out, and whether the mouthpiece is comfortable enough to forget about. This guide covers what to look for, how to test one properly, and the breathing and clearing technique that makes the whole thing effortless.
What a Snorkel Does — and What It Cannot Do
A snorkel lets you breathe with your face in the water while you float on the surface, so you can watch what is below without lifting your head every few seconds. That is its entire job, and it does it well. For snorkelling it is the primary breathing device; for scuba it is a surface tool, used while waiting for the boat, swimming out to a site, or conserving cylinder air on a long surface transit in chop.
What a snorkel cannot do is let you breathe at depth. The limit is not the length of the tube but your chest muscles: once the tube is more than roughly 30–40 cm long, the water pressure on your chest exceeds what your diaphragm can overcome to draw air down, and the dead air already in the tube starts being rebreathed. This is why snorkels are the length they are and why extending one is a genuinely dangerous idea rather than a clever one.
Snorkel design has therefore converged on solving three practical problems: keeping surface water out, getting water back out quickly when it does enter, and being comfortable enough in the mouth to wear for an hour.
The Three Top Designs
Open top
A plain open tube — the simplest and cheapest design, and the one most scuba divers prefer. Nothing to fail, minimal drag, easy to fold into a BCD pocket. It takes water in from waves and every time you duck under, so it demands confident clearing technique.
Splash guard (semi-dry)
A moulded deflector over the top that keeps most surface splash and chop out while leaving the tube open. It fills completely when you submerge, but on the surface it makes a real difference in wind and waves. The middle ground, and the most common choice overall.
Dry top
A float-operated valve seals the tube when it goes under and reopens at the surface. You surface to a dry tube and a clean first breath, which beginners and dedicated snorkellers appreciate. It adds bulk, a moving part that can jam with sand, and slight buoyancy at the top of the tube.
Purge valve
A one-way silicone diaphragm in a sump below the mouthpiece. Water collects there instead of at the mouthpiece, and a light exhale pushes it out downward rather than blasting it up the whole tube. It makes clearing far less effortful and is worth having on any snorkel you use a lot.
Flexible lower section
A corrugated segment between the mouthpiece and the tube. It lets the mouthpiece drop away from your face when you switch to a regulator instead of dangling in front of you, and it lets the tube find its own angle rather than levering on your jaw.
Folding and travel models
Silicone tubes that roll up small enough for a BCD pocket. Popular with scuba divers who want a snorkel available for surface swims without a rigid tube snagging on a line or a wreck. See the snorkel range.
The Mouthpiece Decides Whether You Enjoy It
Everything else on a snorkel is a refinement; the mouthpiece is what you will actually notice. It should sit flat in the mouth with the bite tabs resting between your teeth and your jaw relaxed — you should not have to clamp down to hold it. Silicone that is too hard makes you bite harder to keep the seal, and an hour of that produces genuine jaw ache and, for some people, sore gums the next day.
Check the flange that sits between your lips and gums. It should be thin and soft with no moulding seams or sharp edges, and it should let your lips seal without pursing. If you can feel a ridge running along your gum line in the shop, you will feel it far more sharply after an hour in cold water.
Mouthpieces are sized, and many people are using one that is simply too big. If you find yourself gagging slightly or the bite tabs sit too far back, look for a smaller mouthpiece — they are cheap, replaceable on most models, and transform how a snorkel feels. Orthodontic-shaped mouthpieces suit some jaws and irritate others; there is no substitute for trying.
Bore, Length and Shape
A wider bore moves more air per breath and reduces breathing resistance, which matters if you are working hard. Too wide, though, and there is more volume of stale air to flush out on each breath and more water to clear when it floods. Most quality snorkels sit in a sensible middle range and this is not something to optimise aggressively.
The tube should curve to run alongside your head rather than standing straight up, and it should sit close enough to the skull that it does not lever the mouthpiece sideways. Tubes that are too long increase both drag and dead air; tubes that are too short duck under with every small wave.
Wear the snorkel on the left. This is not arbitrary — the scuba regulator hose comes over the right shoulder, so the left side keeps the two out of each other’s way. Do it from the beginning even if you only snorkel, because the habit carries over.
Attaching It to the Mask
Most snorkels come with a keeper that clips onto the mask strap. The good ones use a quick-release so you can detach the snorkel without taking the mask off — useful on a boat and essential if the snorkel snags on something. Cheap fixed rubber loops force you to remove the mask to remove the snorkel, and they also tend to pull the strap out of position and open the mask seal on that side.
Position matters. The keeper should be roughly level with your temple, high enough that the mouthpiece reaches your mouth without tension and low enough that the tube does not stand proud of your head. If your mask starts leaking on the snorkel side, the keeper is almost certainly pulling the strap and skirt out of alignment — our guide on stopping a mask from leaking covers this among the other common causes. Spare keepers, clips and mouthpieces sit in fin and snorkel accessories.
How to Try a Snorkel Properly
Put the mouthpiece in with the tube running up past your left ear. Let your jaw relax completely and check the snorkel stays in place without you gripping it. Your lips should close around the flange with no effort and no pursing.
Then attach it to the mask you actually dive with and put both on together. This is the step people skip and it is the one that reveals problems: the angle changes once the keeper is fixed, and a snorkel that felt fine loose can pull sideways once it is clipped to a strap. Adjust the keeper height until the mouthpiece sits naturally.
Try at least two or three models. Comfort is the whole specification here, differences between mouthpieces are large, and there is no way to predict from the box which will suit your mouth. Masks, snorkels and fins are traditionally bought together as a set so that fit, keeper width and colour all work — see the full ABC range.
Breathing Through a Snorkel
Float face-down with the mask in the water and your body relaxed and roughly horizontal. Check with a hand that the tube is clear of the surface and pointing upward — until it becomes instinctive, this is worth doing consciously.
Breathe slowly and deeply rather than quickly and shallowly. There is always a volume of used air sitting in the tube, and short shallow breaths simply move that same air back and forth without exchanging it, which leaves you feeling short of breath for no obvious reason. Long, full breaths flush the tube properly.
Take the first breath after any submersion slowly and cautiously — there may be water left in the tube. A useful habit is to rest the tip of your tongue just inside the mouthpiece as you inhale: it acts as a splash guard, and you feel water arrive before you can breathe it in. That single trick prevents most coughing fits.
Clearing the Snorkel
There are two methods and both are worth knowing.
The blast clear is what most people use: as soon as the top of the tube breaks the surface, exhale sharply and forcefully to drive the water up and out. Then take that first breath slowly in case anything remains, and a second sharp exhale finishes the job. With a purge valve, most of the water leaves through the valve at the bottom instead and the effort required drops considerably.
The displacement clear is more elegant and uses less air. As you ascend, look upward and exhale gently into the tube. The expanding air pushes the water ahead of it and out of the top before you reach the surface, so you arrive with a clear tube and no blast needed. It takes a little practice and is worth it if you are ducking under repeatedly.
Safety Points Worth Taking Seriously
- Never hyperventilate before a breath-hold dive: Rapid deep breathing lowers carbon dioxide, which removes the urge to breathe without adding oxygen. It can lead to blackout underwater with no warning. One or two calm deep breaths is the limit.
- Equalise early and often: Your ears should never hurt. At the first sensation of pressure, pinch your nose and exhale gently against it. If you cannot equalise, come back up — never push through pain.
- Always snorkel with a buddy: One dives, one watches from the surface, and you swap. This one-up-one-down pattern is the standard practice in freediving for good reason.
- Watch for boats: A snorkeller face-down is nearly invisible from a boat. Use a surface marker buoy in any area with traffic — see buoys and lifting bags.
- Do not extend or modify a snorkel: A longer tube does not let you go deeper. It increases dead air and breathing resistance to the point where you rebreathe your own exhaled air.
- Keep the tube on the left: Clear of the regulator hose, and consistent with everything you will be taught in scuba training.
Care and Storage
Rinse the snorkel in fresh water after every use, including the inside of the tube — salt and sand collect in the sump and around the purge valve, and grit under a silicone diaphragm stops it seating so the valve leaks continuously. Running fresh water through the tube from the top and working the mouthpiece is enough. If a dry-top valve has been in sand, flush it thoroughly and check that the float moves freely.
Dry out of direct sunlight. UV is what perishes silicone mouthpieces and yellows clear tubes, and a mouthpiece that has gone hard and glossy will make you bite harder to hold the seal, which is where jaw ache comes from. Store the snorkel straight or loosely coiled — a rigid tube stored with a permanent kink in it will never sit right against the head again.
Mouthpieces are consumables. Check for splits at the bite tabs and around the flange at the start of each season and replace them when they appear rather than after they tear mid-swim. A replacement mouthpiece costs very little and restores a snorkel that has become uncomfortable, which is often mistaken for needing a new snorkel entirely.
FAQ
Do scuba divers actually need a snorkel?
It is not required for the dive itself, but it is genuinely useful on the surface — swimming out to a site, waiting for a boat pickup in chop, or conserving cylinder air on a long surface transit. Many training agencies expect one during entry-level courses. Technical and cave divers generally leave it off because a rigid tube on the mask is a snag hazard. A folding snorkel in a BCD pocket is the usual compromise.
Is a dry snorkel better than an open one?
Better for snorkelling, arguably worse for scuba. A dry top means a clear tube and a comfortable first breath every time you surface, which beginners and dedicated snorkellers value highly. For scuba it adds bulk and buoyancy at the top of the tube, introduces a moving part that sand can jam, and matters less because you are breathing from a regulator anyway. Most scuba divers use open or splash-guard designs.
Why can’t I just use a longer snorkel to go deeper?
Two reasons, and both are hard limits. Beyond roughly 30–40 cm, the water pressure on your chest at that depth exceeds what your breathing muscles can overcome to draw air down the tube. And a longer tube holds more exhaled air, so you increasingly rebreathe your own carbon dioxide instead of fresh air. Extending a snorkel is genuinely dangerous, not merely ineffective.
Which side should the snorkel go on?
The left. The scuba regulator hose routes over the right shoulder, so keeping the snorkel left avoids the two interfering. Snorkels are shaped with this in mind, and mask keepers are designed for it. Get into the habit from the start even if you only snorkel — every course you take will assume it.
Why does my jaw ache after snorkelling?
Almost always the mouthpiece. Either the silicone is too hard and you are biting to maintain the seal, or the mouthpiece is too large for your mouth, or it has aged and stiffened. A soft replacement mouthpiece in the right size costs very little and usually solves it completely. Consciously relaxing the jaw helps too — the snorkel should rest in the mouth, not be gripped.
What is a purge valve and do I need one?
It is a one-way silicone diaphragm in a small sump below the mouthpiece. Water collects there rather than at your mouth, and a light exhale pushes it out downward instead of forcing it up the entire tube. It makes clearing much easier, especially for children and anyone still building confidence. The downside is one more part to rinse and eventually replace, but it is worth having on a snorkel you use regularly.
Can I snorkel with a full-face snorkel mask?
Those are a separate product from a mask-and-snorkel combination, and they behave differently. They are easy for casual surface floating, but the large internal volume makes carbon dioxide build-up a real consideration if the design is poor, they cannot be cleared in the way a conventional mask can, and they cannot be used for breath-hold diving because there is no way to equalise or to remove them quickly. For anything beyond gentle surface use, a conventional mask and snorkel is the safer choice.
How do I stop water getting in every time a wave passes?
A splash guard or dry top handles most of it, but technique matters as much. Keep your body flat and relaxed so the tube stays vertical rather than tipping with your head, breathe out through the tube as a wave passes over, and get comfortable with the displacement clear so a small amount of water is a non-event. Fighting the water is more tiring than clearing it.