The SCUBA Diver’s Guide To Choosing The Perfect Diving Drysuit

By Carlos Sagaro

If you ever considered whether a SCUBA diving drysuit is right for you, you came to the right place.  You’ve probably spent some time wondering what the best drysuit is or the what the differences are between a wetsuit and a drysuit are when you are in the water. We know that deciding whether to go dry can be both confusing and scary but stick around because in this article we are going to answer a ton of your drysuit diving questions and steer you in the right direction in your quest to determine whether or not you should dive dry.
Diving Drysuit diver in cave

What Is Drysuit Diving

Drysuit diving is SCUBA diving with a suit that keeps water out thus ensuring that you do not get wet when you are in the water.  The drysuit works by holding water out and maintaining watertight seals around the neck and wrists.  Because water conducts heat 25 times faster than air, having a layer between you and the water will keep you warm.  Drysuits keep the water out completely

Many divers have a misconception of the actual purpose of a drysuit.  See, they are not really designed to keep you warm.  While some do provide some thermal protection on their own (we’ll tackle this a little further on in this article), their main purpose is to keep a diver dry.  While this can be counterintuitive, after all, we all know our wetsuits keep us warm, drysuits are not great at thermal protection on their own.

But, how does a drysuit keep a diver warm?  They achieve optimal thermal protection when they are used with an undergarment.  It's the undergarment that keeps you warm. The drysuit is there to keep the undergarment dry. Drysuit undergarments are designed to be worn underneath the suit and the pieces of equipment that provide thermal protection.  We discuss undergarments with more detail a little further down.

Why Go Drysuit Diving?

Drysuits open up an underwater world that would not necessarily be available to divers who do not use them.  Divers use drysuits to dive in the some of the coldest water on our beautiful, blue marble.  They are also worn by divers who are going to be diving for extended periods of time.

It’s not always about diving in really cold water. I use a drysuit when I dive in the Florida Springs. The water temperature there is about 72 degrees Fahrenheit (22 degrees Celsius) year-round. You’ll see people with no exposure protection whatsoever swimming there. However, since I cave dive there, I’ll be underwater for prolonged periods of time. I could probably get away with diving in a wetsuit, but the drysuit provides comfort by keeping me warm throughout the entire dive. It also makes it much more comfortable when I exit the water because I am already dry and do not need to rush to change out of a wet wetsuit.

By keeping the diver dry, the drysuit allows the diver to maintain body heat over a longer period of time. Without a drysuit not only would diving in colder water be extremely uncomfortable, it could also lead to hypothermia, a dangerous condition which occurs when you lose too much body heat.

How Cold Can You Dive in a Drysuit

People routinely use drysuits to dive under ice. So as long as the water hasn’t completely frozen over yet, and provided that you are using the correct suit and undergarment, you can use them to dive in waters as cold as 34 degrees Fahrenheit (1 degree Celsius).

Diving Drysuit diving in ICE

Whether in the artic, Antarctic, beneath an ice-covered lake near a mountain in Russia, in the freezing waters of the cost of the American North East, or off the coast of the cold waters of the UK, the proper drysuit and undergarment can keep you warm enough to enjoy this otherwise inaccessible underwater world.

Diving Drysuit Divers in mountain lake (1)

How is Drysuit Diving Different than Diving in a Wetsuit?

By now you know that drysuits work very differently than wetsuits. Wetsuits keep you warm by keeping the water that is inside the wetsuit and close to your skin at a warmer temperature than the water you are diving in. They keep you completely dry.

Because you are completely dry you now have to be concerned with an extra air space while diving. Because your body is completely sealed inside the drysuit the space inside the suit creates an air space. This air space if not managed properly can become dangerous.

If you would like to learn more about wetsuits check out the article below:

https://greatdivers.com/scuba-gear/wetsuits/

Suit Squeeze

As divers, we know that because of Boyle’s law gasses will compress as we descend. The air space inside your drysuit is no exception. If gas is not added to the suit as you descend underwater the suit will compress around your body to the point that moving will become difficult. It can even cut off your circulation and cause bruising due to how tightly a suit can compress around you.

For this reason, all drysuits have an inflation valve (usually in the front) so that the diver can add air as he or she descends into the water.

Diving Drysuit Inflator
Diving Drysuit Dump Vavle
Dump Valves

Similar to the way that you need to add air to your suit as you descend, you also need to dump air from your suit as you ascend. This is the same as managing the air space in your BCD wing. In order to dump air from your suit, it will likely have at least one dump valve usually positioned on the upper arm (below the shoulder).

Managing the Additional Air Space

Much of learning to dive dry is about learning how to properly add gas to your suit while descending and dump gas from it while ascending. It can be trickier than it sounds. Too much gas will throw off your buoyancy. It can also create a bubble inside your suit which can travel around as you shift positions. This is something you want to avoid!

If you have too much gas inside your suit and the extra gas makes its way towards your feet, it can cause a dangerous situation where you become inverted in your suit. Because there are no dump valves near your feet you may begin to ascend uncontrollably towards the surface feet first.

This is why you may want to consider a drysuit course or at the very least learning to dive dry from an experienced and qualified instructor.

Suit Flooding

Another thing that’s different about drysuits is that you have to consider the possibility of a it flooding. If one of the seals become compromised or your suit tears during the dive it may become flooded with water. In very cold waters this can be dangerous. It’s also why drysuit undergarments need to be made from a material which will keep you warm even when wet. This means you can’t just throw on a cotton sweater and jogging pants underneath your suit.

Drysuit Buoyancy Considerations

Drysuits are generally more buoyant than wetsuits. How much more will depend on the suit material and the undergarments being used.

You’ll need to account for this difference in buoyancy by either adding more weight to your SCUBA diving rig, using a stainless steel backplate to add weight to your rig, or using a SCUBA tank that is more negative than the one you use while diving wet.

In order to determine the correct amount of ballast, you should perform a buoyancy check in the drysuit using the undergarments you intend to dive with. Note, changing your undergarments may change your buoyancy requirements in a drysuit.

Drysuits and your BCD

Because drysuits hold an additional air space some people wonder if they can replace a BCD? The answer is NO! The airspace is the suit is not as easy to control as the one in your BCD. It’s also not designed to balance you out in the water. You should never rely on your drysuit alone for buoyancy. Some divers consider a them a redundant form of buoyancy control should your BCD wing fail. While in an emergency this may be possible it is less than ideal.

What are drysuits made of?

Drysuits come in several different materials.  Neoprene, crushed neoprene, vulcanized rubber, and trilaminate are some of the most common.  The most popular of these is trilaminate and neoprene.

Vulcanized Rubber

Vulcanized Rubber Diving Drysuit

Vulcanized rubber suits are more often used in commercial settings and are not very common for recreational or technical diving. Some of the early drysuits were made of this material, but more modern materials have made these suits rare in the diving community.

Neoprene, Crushed Neoprene and Compressed Neoprene

Neoprene suits are made of the same material as your wetsuit except that they are designed to hold an air pocket between you and the outside rather than a layer of water.  The main benefit of neoprene suits is that they provide some inherent thermal protection on their own.  Still, you will need to use an undergarment in colder water or on longer dives.

Neoprene Diving Drysuit

If you decide to go with neoprene, there are a few things you will need to consider.  First, neoprene suits require the diver to add more weight.  This is especially true towards the end of your dives when you are performing safety stops at shallower depths while breathing out of a tank that is less full. 

They tend to be harder to put on than trilaminate suits and take much longer to dry.  This is important because they must be stored completely dry.  If you will be travelling, they are harder to fold and weigh more.

Finally, you’ll need to decide between a neoprene, crushed neoprene or compressed neoprene suit. The difference is that “compressed” and “crushed” neoprene take an existing neoprene material and using heat and compression compress the material so that it won’t compress as much underwater as you dive deeper. This makes it so the buoyancy characteristics of the suit won’t change throughout the dive. It also makes the neoprene more durable than that of a wetsuit. Different manufacturers use different processes to create their versions of crushed or compressed neoprene so it may be difficult to compare one brand to another.

Trilaminate Diving Drysuit

Membrane Drysuits

Membrane drysuits have become much more popular for recreational and technical diving. Most membrane suits are made out of a trilaminate material. The terms membrane and trilaminate are used interchangeably by most in the dive industry. The trilaminate suits are made out of two to three layers of durable material. The outside is usually a nylon, polyester or Kevlar material.  There is usually a butyl rubber membrane in the middle.  They are extremely durable and easier to patch than neoprene suits.  They are also more resistant to deterioration over time.

These suits offer some benefits that have made them more sought after. They are much less buoyant than their neoprene cousins.  They are easier to put on and take off than the neoprene suits, and they are easier to move around in than their neoprene cousins.  They are not as positively buoyant as neoprene so they will not require as much ballast.

Trilaminate suits also allow you to layer as much or as little undergarment material as needed depending on the diving conditions. This makes them ideal for both cold and warm water diving. They also dry much faster and are easier to fold for travel.  On the other hand, they offer little to no thermal protection so you will have to use an undergarment with them. 

The Parts That Make Up Your Drysuit

You already know that most drysuits will be either a membrane / trilaminate material or some form of neoprene, crushed neoprene or compressed neoprene. You also know that that the suit will need to have an inflator and a dump valve to manage the air space inside. Below are some of the parts of the suit that you need to know about when looking at and considering different types of suits.

Drysuit Seals

Diving Drysuit Wrist Seal
Drysuit Neck Seal

The seals of the drysuit are designed to keep air in and hold water out.  There are two types of seals: Neoprene and latex.  Neoprene seals are less expensive to replace than latex by are a little difficult to slide through.  If you purchase your own suit, you can trim the seals as needed.  This allows you to create a more comfortable fit.

The most common material for drysuit seals is latex. If you happen to be allergic to latex, silicone seals are also available. The problem with all seals is that eventually they will all tear.  When a seal tears, you’ll need to have it professionally re-installed since it is attached directly to the suit.

Many manufacturers make “wrist rings” or “Zip seals” which allow the diver to change out the seal themselves. With these systems, the seals are attached to a ring which in turn is attached to the drysuit. The seal attaches using a system that is similar to that of a zip lock bag. The advantage of this type of system is that, should a seal tear, you can repair it yourself on the fly.

The disadvantage of these systems is that the ring makes the suit a little bulkier around the ring where the seals attach. Also, because it uses a seal that is similar to that of a zip lock bag it’s possible for this seal to become undone and allow water to enter the suit.

Drysuit Zippers

The zipper is an extremely important part of your suit.  Aside from being the most expensive part of the suit to replace, it requires regular maintenance.  You should wax your drysuit zipper as recommended by the drysuit manufacturer with the recommended wax.  Apply the wax on the outside of the teeth so that you do no gum up the inner sealing surfaces of the zipper. This is not a place to skimp.  A dry suit sipper can cost 300 to 500 dollars to replace.  Also, if it breaks, it ruins your diving day and even future dives as they must be repaired by a professional.

Diving Drysuit Zipper Closed
Diving Drysuit Zipper open

The zipper position is another thing that you will have to consider when buying your drysuit.  The zippers can be positioned across your shoulders, in the front, or on the back of your suit.  I recommend you try on a few and see which you prefer.  I like the front zipper because I can zip up the suit myself. 

When zipping your suit, do not yank hard on the zipper.  Zippers are extremely sturdy, but they can break.  Make sure to treat them as gently as possible. Stretch the zipper out as much as possible and steadily pull on the zipper until it closes.

Knee and Elbow Pads

Over the years the knees and elbows of many suits tend to get worn down the most since these areas tend to rub the most while getting ready to go diving. Many suits reinforce these areas with pads. With many suits this may be an option only available with the more premium models, but it is something worth considering.

Drysuit Boots

There are several options when it comes to the boots of your drysuit. Some suits come with the boots already sewn into the suit itself. Others come with a sock-like foot cover allowing you to place a boot on top of the sock. The boot is sometimes referred to as a “rock boot”.

The advantage of having the boot be a part of the suit is that it is streamlined and allows you to use a larger variety of fins. The disadvantage is that if the boot wears out, you’ll need to have it replaced professionally.

Diving Drysuit Boot

The advantage of a rock boot that fits over a sock like finish is that you can easily swap out boots when they become worn out. The disadvantage is that rock boots tend to be bulkier and sometimes the foot pockets of the same fin you use with a simple bootie when diving wet may not fit as comfortably. This may mean you need to get a fin with a larger foot pocket to use with your drysuit.

Drysuit Suspenders

Suspenders are a feature which many drysuits have. The suspenders make it easier for you to put on your drysuit. They also allow you to wear your drysuit with the top part off while you are on the surface and preparing to dive. This makes it more comfortable when the air temperature is not as cold and you don’t necessarily want to have the entire suit on.

Diving Drysuit Suspenders

Drysuit Gloves

Diving Drysuit Gloves
Diving Drysuit Mittens

If you will be diving in cold environments, you may need to dive with dry gloves as well. The gloves like the suit are water-tight keeping your hands dry throughout the dive.

Dry gloves can either be worn over your existing wrist seals or they can be connected to an attachment ring or zip seal if your suit has that option. Dry gloves come in gloves, mitts and three finger mitts. Mitts and three finger mitts are the warmest option, but you lose dexterity with these options.

Whatever option you choose, you should try it out before diving. Make sure you can reach and unclip any equipment you use during the dive and purge your regulator with the gloves on.

Drysuit Hood

The hood you wear with your drysuit is an important part of staying warm underwater. The hoods are typically made out of neoprene and work the same way that wetsuits do. It’s extremely important to try on the hood and make sure it’s a snug fit. It’s also important that it doesn’t fit too tightly around your neck since it can put pressure on the carotid artery, causing a reflex which slows the heart resulting in poor oxygen delivery to the brain. This can cause light headedness and even unconsciousness. This can also happen if neck seals that are too tight!

The Dump Valve’s Position

As mentioned previously, most manufacturers position their dump valves just below the shoulder.  This position allows you to move your arm to ease dumping air when you are in a full horizontal as well as a vertical position.  This is the best position because it does not require you to contort your body into awkward positions to dump gas from your suit.

Please note that there are a few dry suits manufacturers that position the dump valves higher on the shoulder, but this is not recommended as it makes it more difficult to dump air depending on your position in the water.

Diving Drysuit Dump Valve position

Please note that there are a few dry suits manufacturers that position the dump valves higher on the shoulder, but this is not recommended as it makes it more difficult to dump air depending on your position in the water.

Fitting your Drysuit

This is of paramount importance.  It is imperative that you try on the dry suit you are planning on purchasing before you buy it.  One thing to also note is that you should try the suit on with the undergarments that you plan on diving with.  This is crucial to determining proper fit. Different manufacturers cut their suits differently so a medium from one manufacturer may be a large with a different manufacturer.

Diving Dry suit fit

The drysuit should allow you to have full range of motion when you are diving.  Make sure you can reach your valves should you need to perform an emergency shut off. Also make certain that you have as close to full range of motion as possible.  If your suit does not fit properly, you will never be comfortable when wearing it which will make you enjoy your diving less and add to stress load when underwater.  It can also create a dangerous situation because you possibly could not be able to reach your equipment easily or at all. 

Off the Rack Vs. Custom-Tailored Suits

It is possible to get a dry suit custom made for you.  Manufacturers will have you measure your body is several different points depending on their specific measuring guidelines.  They will then tailor a suit to fit you specifically. 

The benefits here are many.  The suit will fit you better which will allow for better movement in the water.  This will reduce or even eliminate restrictions in movement which will provide much more comfort.  A better fitting suit will have better buoyancy characteristics because it will be less likely to create air pockets.  This will make it easier for you to maintain neutral buoyancy and trim when diving. You can add gear pockets wherever you like (more on this later). 

One of the factors that should be taken into account when making this decision in the price.  Custom fitted suits are more expensive than their off-the-rack counterparts.  A drysuit is a big investment and purchasing a custom fit suit adds to the expense.

The drysuit should allow you to have full range of motion when you are diving.  Make sure you can reach your valves should you need to perform an emergency shut off. Also make certain that you have as close to full range of motion as possible.  If your suit does not fit properly, you will never be comfortable when wearing it which will make you enjoy your diving less and add to stress load when underwater.  It can also create a dangerous situation because you possibly could not be able to reach your equipment easily or at all. 

Drysuit Undergarments materials

There are two things all undergarment materials have in common. First, they are designed to keep you warm. Second, they need to be able to keep you warm even if they become wet. Keep in mind that a drysuit is always in danger of having its seals compromised. For this reason, whatever you wear under your it has to be able to keep you warm even if it becomes wet.

A drysuit undergarment is designed to be worn underneath your suit while maintaining warmth.  Without them, you will lose body heat rather quickly rendering your drysuit useless.  Undergarments are an essential part of every drysuit.  A great tip to remember is that undergarments can be layered.  Anyone who has been in cold weather knows that layering is an excellent way to keep warm.  This same concept applies to your drysuit underwear.

Drysuit Undergarments are made of several different materials.  

Thermal under

Thermal Undergarment

Drysuit Loft Undergarment

Loft Undergarment

Diving Drysuit Fleece Undergarment

Fleece Undergarment

Fleece undergarments are designed to be soft.  This material is very comfortable.  Fleece undergarments are great as a base layer in your drysuit arsenal. Fleece also has a tendency to wick moisture off of the body which is good should you sweat of should you have a small leak in your dry suit.  Another aspect of these that make them popular is that they are smaller, so they are easy to take with you when you travel.

Merino Wool is known for its ability to maintain body temperature well.  This is specifically designed to repel water on the outside while absorbing it when worn against the skin.  The benefit here is that it will not get soaked should your suit leak while wicking away sweat from your body.

Loft undergarments resemble the same material used for sleeping bags.  As the name suggests, these undergarments are thicker and are excellent at maintaining body heat in freezing waters. Due to their design, it is recommended to wear a base layer that wicks away sweat so that you do not feel wet while diving.

The question is, which undergarment will you need?  It truly depends on the temperature of the water that you are diving in.  Undergarments are measured by their thickness which is measured in grams.  There is a range of thicknesses available and each manufacturer will spell out the recommended water temperatures for the corresponding undergarment.  It is also a good idea to contact local divers who are familiar with the area where you intend to dive to see what they have been using and what they recommend.

Accessories for Drysuits

There are many accessories that you can purchase to personalize your drysuit.  What you decide to buy wholly depends on your preferences and needs when you are underwater.

Drysuit Pockets

Pockets can be either installed by the manufacturer or can be purchased and glued on by the diver. The pockets will often that have D-rings inside them to attach equipment. You can use clips on your gear, so you do not inadvertently lose you gear when you reach inside. The pockets are usually placed on the thigh on either side of the body or both depending on your needs.

Diving Drysuit Pocket

Heated Vests

If you want additional warmth without additional layers you may be interested in a heated vest. The vest is worn underneath the suit and needs to be connected to an external battery.  It is important to note that, should you decide that you want to add a heated vest, you will need to add a connection that allows you to connect the battery to the vest you are wearing underneath.  Some divers even carry more than one battery with them should they be on a long dive and the first battery runs out of power.

Pee Valves

Diving Drysuit Pee vlave hose
Drysuit Pee valve

Pee Valves are an option for drysuits as well.  These allow you to urinate with your dry suit on. These are typically used when you will be doing longer dives. You will have to attach a connecter to the suit that then attaches to a condom catheter that attaches to the penis.  For women there are internal catheters as well as an external one.  This will allow you to pee when you are diving and is an option to consider if you are going to go on long dives.  The valve itself is connected to a rubber hose which then connects to the end of the catheter. 

It is highly recommended that you follow the instructions of the specific pee valve you purchase to properly learn how to use the pee valve.  If you are going to use a pee valve then we recommend that you add a pee valve to your dry suit when you purchase it.  It is not an expensive thing to add and you can always decide not to use it.  It is better to have it and not need it and installing one later will end up costing you more.

Argon Bottles

Some divers, especially in the technical diving community choose to have a separate cylinder dedicated to inflating the drysuit. When a separate cylinder is used Argon is usually the gas of choice. Argon has a lower thermal conductivity than air or nitrox, so it helps keep the diver warmer during the dive. Because argon can be dangerous if inhaled, the cylinder used to contain this gas need to be clearly marked as containing argon and only used for this purpose.

Drysuit Gaiters

As mentioned earlier one of the tricky parts about learning to dive dry is avoiding putting too much gas into your suit. The most dangerous part about having too much gas in your suit is if you allow that gas to travel to your feet. Drysuit gaiters are wraps that go around the lower part of your legs (around your calves) in order to avoid gas traveling to that part of the suit. The gaiters can even be built into the suit as a feature. While this can help beginner divers still getting accustomed to a dry suit our recommendation is to learn to put the correct amount of gas in your suit and the maneuvers necessary to empty gas from your feet if it should happen. Gaiters are really a crutch that shouldn’t be relied on in the long term.

Alterations

One of the greatest benefits of drysuits is that they can be altered to fit your body better. This allows you to achieve greater comfort over the long run.  Of course, this can only be done if you own the dry suit.  You can cut the seals to ensure a better fit.  You can change the boots depending on whether you prefer one type boot over another.  You can even shorten the sleeves and legs of a suit.  You can even change from dry gloves to wet gloves.  Lastly, you can purchase a suit that is custom fit for your body.  Be aware that custom suits do cost more but the investment may be worth your while if you intend on using your suit often.

Dry Suit Maintenance

Dry suits do require regular maintenance to maintain proper function.  Also, regularly maintaining your drysuit will ensure that it lasts longer. 

Seal maintenance is vital.  Make sure to be careful when donning and doffing your suit that you are not wearing jewelry or hair ties.  Watch to make sure that you do not dig your nails into the seals when you stretch them out.  Check for splitting or cracking of the seals and have that attended to before your dive. 

The zipper is the most expensive part of the suit to repair.  Make sure you store it in the open position and regularly lubricate it with wax to maintain its integrity.

A poorly maintained dry suit will not last as long as one that is properly taken care of.  More importantly, drysuit failure can be very dangerous.  Because your drysuit is being used to keep you comfortable in very cold water, a failure can lead to an emergency situation.  If your suit fails while you are underwater, you can suffer form hypothermia.  This can make It more difficult for you to decompress, focus, and function.  It can even cause buoyancy problems.

Make sure to rinse you suit well after each dive, especially in saltwater.  Make sure you hang your suit so that it can dry properly before storing it long term.  A properly kept and maintained drysuit will last you for years and provide excellent performance throughout its service life.

Drysuit Training

One of the most common questions that we are asked is “should I get training to dive a drysuit.”  The short answer here is “yes!”  While diving in a drysuit is not as hard as you may think, it does offer its own set of circumstances that can be acclimated to much more easily if you are properly trained.

Diving Drysuit divers traning

I remember the first time I dove dry.  I had my own misconceptions as to how it would feel.  I was worried about things like: I am going to feel squeezed?  Will it be hard to move?  Will I be able to reach my valves in an emergency?  What if I end up “feet up” in the water? Is this thing going to stay dry?  The truth is that none of those things were warranted.  If you properly adjust the air in your suit, you will not feel squeezed.  A properly fitting suit does not restrict movement.  And, yes, my suit did keep me dry!  All my fears of diving in a drysuit were not very warranted.

With that said, there are a few things that you need to know.  How to react in an emergency situation.  How your drysuit will affect your trim and buoyancy, how much more weight you will need?  Proper training will address all those things and much more. 

It is important to note that an overly filled drysuit will make it difficult to maintain trim and buoyancy.  Your drysuit does have positive buoyancy but should not be used for primary buoyancy compensation.  It can be used in an emergency situation but, aside from that, you should only add as much air into your drysuit as you will need to keep it comfortable and prevent a drysuit squeeze.

In time and with proper training, your drysuit will feel as natural underwater as your wetsuit does. This is why it’s important that you find a qualified instructor if it’s your first time diving in a drysuit!

In Conclusion

So, you probably came into this wondering “should I get a drysuit?”  I hope that the information in this article has helped you get a better grasp of what owning a drysuit entails. 

Whether or not you should dive dry ultimately depends on the type of diving you’re doing and how cold you get while you are doing it.  In the end, diving dry can be as natural as diving wet once you get used to doing it.  Practice and experience make all the difference.

If you do decide that a diving drysuit  is for you, you should get assistance from a professional dive shop. They can help you in choosing a suit that fits you properly, choosing the correct undergarments and even help with training so that you remain safe.

Did we miss anything about drysuit diving?  Have any questions?  Please comment below and let us know!

Want to Learn more?  Below are some recommended articles where you can find out more about Diving Drysuits.