Sailing Wetsuit Basics: What Are They and How do They Work?

Zhik Wetsuit

What is a sailing wetsuit?

They are one or two piece suits made of foamed neoprene that is worn on smaller sailboats to provide:

  • Thermal insulation against cold water (and air)
  • Padding against bumps and bruises
  • Coverage to prevent skin abrasion
  • Sleek fit help prevents getting caught on boat rigging
  • Buoyancy

Sailing wetsuits are specifically designed to accommodate the posture and movements of sailing.  They will also be reinforced in the seat and knees to properly protect the suit from boat abrasion.  Diving, surfing, waterskiing, windsurfing, and general watersports wetsuit are built for different postures and activities which will hinder your onboard movements.  If you intend on using a wetsuit for sailing, be sure it is a sailing specific suit.

APS is the World Leader in Outfitting Sailors.  Shop our:
– Unisex Wetsuites
– Women’s Wetsuits 

How do Wetsuits Keep you warm?

A wetsuit’s primary value is to keep you warm in the water (and out) through a range of warm, cool, cold, and frigid temperatures.  This is important to keep in mind as water pulls heat out of your body 25 times faster than air.  They do this in several different ways.


Unlike a dry suit, wetsuits will be wet inside.  The water that enters the suit does not aid in keeping you warm.  In fact, when you go in the water for the first time on a day, the cold water seeping into a wetsuit can be initially quite shocking and uncomfortable.  If a wetsuit was able to keep all water out, it would be an even better insulator and more comfortable, but it’s a wetsuit design.

A properly fitting wetsuit should be snug (second skin fit) and squeeze you all over.  When you enter the water a very thin layer of water will squeeze between your skin and the wetsuit.  If the wetsuit is loose then too much cold water will flood in and fill these gaps between the wetsuit and your body.

With a properly fitting, quality wetsuit, the thin layer of water that seeps in will be initially cooling but be quickly warmed by your body’s trapped heat.  When you are moving about in the water, the thin layer of warm water in the suit helps keep new cold water from entering as the suit is already ‘full’ of water.  Having a good fit at the ankles, wrists, and neck will also help prevent new cold water entry, also known as ‘flushing’.

With a poorly fit wetsuit, much more water will be able to enter the suit initially.  It will take your body much longer to warm all of this water, thus robbing your body of more heat.  If there is too much water your body may never be able to heat the water.  When you are moving about in the water a loose fitting suit ‘flushes’, and new cold water enters.  This mixes with or displaces the water your body worked so hard to heat up.  Constant flushing will reduce a wetsuit’s ability to insulate you in a very substantial way.

If the suit does not fit properly, then any of the features or materials of the best performing wetsuit will make no difference.  It is fair to say that a well-fitting thin wetsuit will be much warmer than a loose fitting thick wetsuit.  If the suit does not fit, move on to another brand, style or cut.

Tip: Cheap wetsuits found at discount stores will be basic in design, materials, and fit.  They may be fine for warmer weather sailing, but if you will be sailing in cool, cold or frigid weather where you need a suit to really perform and keep you warm, steer clear of them.

Insulation – Neoprene

Primarily, warmth from a wetsuit, or insulation from the cold, is provided by the neoprene material it is made of.  Neoprene is basically elastic synthetic rubber with very good insulation properties thanks to millions of microscopic bubbles (microcells) trapped inside the material.  These cells are filled with either air or nitrogen gas (better insulator).  These bubbles make up the basic insulation neoprene.

With a well-fitted wetsuit, your body will have warmed the thin layer of water in the suit, and the heat in this water and from your body will be pressed right up against the neoprene.  On the other side of the neoprene is either cold water or air that is constantly absorbing this heat, as neoprene is not a 100% efficient insulator.  This is where thickness comes in.  The colder the temperature outside the suit, the thicker the neoprene needs to be to retain wetsuits work

For sailing purposes, neoprene is 1 to 5mm thick (Sometimes you will see a lightweight top made with 0.5mm neoprene).   Neoprene will generally have a thin, stretchy, lycra facing bonded to both outsides and inside to prevent damage to the soft neoprene.  This is called double-sided neoprene.  The thicker the neoprene, the warmer the suit.  In some winter suits for frigid conditions separate 3-5mm thick tops and bottoms will overlap over the core to give you a 6-10mm thickness in that area.

While neoprene is stretchy, it does require you to stretch the material with every movement you make while sailing.  The thicker the neoprene, the more energy it takes to stretch, thus causing wearer fatigue.  There is a tradeoff between making the wetsuit warmer by using thicker neoprene throughout the suit – mobility.  To combat this it is common for thicker neoprene to be used around the core and legs to maximize insulation, and thinner neoprene through the shoulders, underarms, and arms to maximize mobility.  When this is done suit thickness is referred to like 2/3 – which is 3mm in the core and legs, and 2mm in the arms and shoulders.  For colder water, you may find a manufacturer describing it as a 3/4/5 which generally equates to 5mm core panels, 4mm legs and 3mm arms and shoulders.

High-quality suits will use ‘super stretch’ neoprene which requires less energy to move in and are thus less fatiguing.  ‘Super stretch’ material will have more insulating bubbles which usually have nitrogen gas in them for better insulation.  Thus super stretch suits can be thinner than traditional neoprene while providing the same amount of insulation.  Suits made of super stretch are also easier to get in and out of and provide a better fit.  Fit and thickness remaining the same, always choose a suit made with the easiest to stretch neoprene.

TIP: Some manufacturers use neoprene that has a silver ‘titanium’ coating on the inside facing surface.  The claims are that this feature reflects radiant heat from your body back, and prevents it from escaping through the neoprene to the cold outside environment.  Opinions vary, but this is not a major factor in choosing one suit over another.  If you can get a suit with it, great, it will help, but fit and neoprene thickness is the top priority.

TIP: Cheap wetsuits will use lower quality neoprene that is less stretchy, and therefore more fatiguing; and will have fewer microcells, and so a lower insulation value.  That said, if you have not tried on a wetsuit in 10+ years, you may be pleasantly surprised at the advances in neoprene production, and just how soft and stretchy the good neoprene has become.


Insulation – Internal Linings

All wetsuits in the past used to be simply lined with a nylon or Lycra facing on the inside and out, and that was it.  Pretty basic.  Now internal linings play a significant role in wetsuit insulation and comfort.  These linings, ‘thermal fleece’, may be located on just the core area of the suit for cold temperatures, or throughout the entire suit for suits designed for frigid temperatures.  The goal of the internal lining is to provide additional insulation and warmth, allow a thinner neoprene to be used, to be as flexible as the neoprene it is attached to, not to soak up water, and to dry as quickly as possible.wet suit thermal liner

The fibers in this fabric are usually made of polyester and contain large amounts of trapped air which is the best way to insulate.  The fibers are lightweight, hydrophobic (don’t absorb water), dry very quickly (with your suit turned inside out) and are stretchy.  Every manufacturer has their own trade name for this material, but they all do basically the same thing – add a factor of warmth.

So in addition to the thickness of the neoprene, which is still the number one factor in deciding how warm a suit will be, there is the additional consideration of how much of the suit has an internal insulation lining.  A 3mm super stretch wetsuit fully with a full plush lining can insulate as well as a traditional 4mm or 5mm neoprene suit.


Gear that Complement Wetsuits

Rash Guard Top (and Pants): These are stretchy, non-insulated tops, which fit snugly to the body and dry quickly.  The most effective type of top will be long in the torso, with long sleeves and a mock turtleneck.  They prevent abrasion from the boat and equipment when sailing and protection from the sun’s damaging UV. They are most popular in surfing to protect against abrasion from the mixture of sand and wax on the surfboard when it is too warm to wear a wetsuit.  In warmer conditions, rash guards can be worn under less expensive wetsuits that have seams and materials that are abrasive to the skin.  In higher quality wetsuits, you should avoid wearing them underneath as they can impede the designed performance of the suit, and the suits are more comfortable directly against the skin.  Rash guard pants can be worn as a standalone piece also, but are not generally worn under any wetsuit.

Hydrophobic Thermal Tops (and Pants):  The tops are generally a rash guard style cut, but made of a lighter Lycra fabric.  The inside of these tops will be faced with a thin insulating polyester lining.  The fibers of the lining are lightweight, hydrophobic (don’t absorb water) and dry quickly.  They can be used as a standalone top for warm temperatures, or as a base layer in a wetsuit to add a thin additional insulation layer.  Pants can be used in a similar fashion as the top, but are much less likely to be used inside a wetsuit.


Types of Wetsuits


These tops are made of neoprene to create insulation and seek to minimize water intrusion to maximize sustained warmth.  The thickness of neoprene ranges from 1mm to 3mm’s, with or without a thermal liner – for sailing through cool, cold and frigid temperatures.  They are designed with long sleeves and mock turtlenecks for maximum coverage.  Some thin neoprene tops have only crew necks for use in warmer temperatures.  These pieces are matched with neoprene shorts, pants, hikers and long johns in thicknesses that are appropriate for the temperatures.


These will create minimal warmth, but offer padded protection when sitting on, or hiking on a hard deck.  For this reason, the neoprene is purposely thicker and may have a double layer on the back of the legs and buttocks for even greater comfort.  Water intrusion into the shorts is variable due to the large waist and leg openings.



Neoprene pants, like tops, provide insulation and seek to minimize water intrusion to maximize sustained warmth.  The thickness of neoprene ranges from 1mm to 2mm’s, with or without a thermal liner – for sailing through warm and cold temperatures.  They are cut high wasted, with long legs and the fit at the waist and ankles that seeks to minimize water intrusion.  Match these to neoprene tops that are appropriate for the temperatures.


This is a classic standalone design for many watersports, with short legs and arms

and a mock turtleneck cut.  These are usually in 2/3mm neoprene with a rear zipper entry.  For cool weather sailing these provide a basic solution to staying warm.



Most all quality dinghy hiking ‘pants’ are made of neoprene.  The ridged support that runs along the back of the thigh to protect your legs when straight leg hiking will be permanently sewn to the ‘pants’ or consist of a sleeve that is slid over your thigh prior to putting the pants on.  The ‘pants’ come in different styles – shorts, ¾ pants, ¾ leg with suspenders, and full leg with suspenders.  Some sailors may make their wetsuit choice independent of their hikers, and wear their hiking pants overtop of their chosen wetsuit.  A more integrated and easier to move in solution is to factor hiking pants in as the bottom half of your wetsuit outfit.  In this case, and when sailing in cool temperatures, you may choose 3/4 length hiking pants with suspenders, and for cold and frigid conditions full-length legs.  The very high wasted cut and ankle ‘seals’ minimize water intrusion.  Match these to neoprene tops that are appropriate for the temperatures.

Long John

These give you full core and leg coverage, and also the ability to use a thicker, warmer suit with a thinner neoprene top.  This keeps your core and legs warm, and your arms shoulders with more free freedom of movement.  For cool to frigid these will run from 3mm – 5mm, with or without a thermal liner.  Thinner (2mm) long johns may be used as a light insulator, with a non-neoprene shirt worn beneath it in warmer temperatures.  For frigid temperatures, you will need to match these with a correspondingly thick top to stay comfortably warm.  Men’s may come with a relief flap or zipper in the front such that you do not have to take down your long john in order to relieve yourself.  Women’s do not have a relief feature.  Match these to tops that are appropriate for the temperatures and desired freedom of movement – thinner neoprene or non-neoprene tops, to make movement easier, temperature allowing.

Short Arm

These, like the shortie, tend to be standalone wetsuits for temperatures just a bit too cool for a shortie.  Typical construction is 2/3mm neoprene.  For cool weather sailing these provide a basic solution to staying warm.


Full Suit

These are one piece suits designed for cold and frigid conditions and are the alternative to a sailing dry suit.  They are often referred to as ‘steamers’ due to the steam they can give off when taking them off.  Historically these will have 5mm neoprene throughout the core and legs, with a combination of 3mm and 4mm neoprene in the crotch, arms, shoulders, and underarms to provide ease of movement.  More recently you will find the top of the line suits using 3mm super stretch neoprene, with a thermal fleece lining throughout the suit for excellent mobility and insulation throughout the suit.  Men’s may come with a relief flap or zipper in the front such that you do not have to take down your long john in order to relieve yourself.  Women’s do not have a relief feature.


To maximize a wetsuit’s insulation you want to minimize cold water flushing into your suit, and maintain the thin heated layer of water already there.  Zippers on wetsuits are not waterproof and allow water to seep in, and are therefore kept as short as possible.  A well-performing wetsuit will have what is called a baffle or ‘batwing’.  This is a strip or flap or neoprene that sits behind the zipper and traps any water that goes through the zipper.  Look for it.



This is the simplest way to join two pieces of neoprene, but the least effective way of keeping water out.  The two pieces are rolled together and then stitched.  Thee overlock stick used drastically reduces the flexibility and stretch of the seam.  It can also leave a bulge running down the seam on the inside of the wetsuit, making it uncomfortable and cause chafing.  You will only find this stitch on cheaper, low-performance wetsuits.  Overlock seamed suits are not recommended.

Tip: Not found in quality sailing wetsuits


This stitch is used with two overlapping pieces of neoprene.  The stitches are wide and go completely through the waterproof neoprene.  As the seam between the neoprene is not glued together, and the stitches have created holes in the material, these seem to allow water to seep through them and into the suit.  This type of seam should only be used on wetsuits for warm and cool temperatures.  Quality wetsuits for use in cool, cold or frigid conditions will not use this stitch due to it leaking water into the suit.

Tip: Found in sailing wetsuits meant for sailing in warmer temperatures.

Blind Stitch

This stitch is used in quality wetsuits.  Neoprene pieces are glued together and then stitched halfway through the material to strengthen and ensure a watertight seam.  Because the stitching does not completely penetrate the materials and the seam is sealed with glue, no water will enter the suit, and this maximizes warmth.  Additionally, a seams may be partially or fully tapped on the inside to protect from chafe and abrasion damage.  Also, the outside of the seam may have a liquid rubber applied to reinforce and strengthen the seam.  Blind stitched seams create a quality wetsuit.

Tip: Most common stitch found in high-quality sailing wetsuits meant for cold and frigid temperatures.

Welded: This is the most durable and flexible waterproof seaming available and is found on the highest performance wetsuits.  A urethane glue is used to permanently join the panels of neoprene.  Then a liquid rubber is applied to both the inside and outside of the seams to reinforce and strengthen the seam.  These seams are comfortable against the skin and offer the most elastic of seems available.  Welded seamed suits are recommended for use in water that is below 52°.

Tip: Not commonly found in sailing wetsuits, but desirable.

APS is the World Leader in Outfitting Sailors.  Shop our:
– Unisex Wetsuites
– Women’s Wetsuits

Wetsuit images courtesy of Zhik, Gill, Musto & Sea Australia.

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