Wetsuits How they work: How to choose one


There is a lot to consider when you are first go scuba diving. Its an amazing hobby and one that can add a lot to your life. Being in the oceans evokes deep emotional responses that are satisfying.

That said, to make the most of this fantastic experience you need to feel comfortable and safe. Wetsuits are an important part of this. We are going to take you through all aspects of a wetsuit. The history, how they work and important points when choosing your wetsuit. Enjoy all!


Who invented wetsuits?

The invention of the wetsuit was credited to Hugh Bradner (1915-2008). A university of California at Berkeley physicist. Who developed the idea while working for the US Navy in 1951. While Dr Bradner was responsible for the modern day neoprene wetsuit. He is not the person who invented neoprene itself. Neoprene was developed by Wallace Carothers, the pioneer of Nylon.

He was actually not the first person to conceive of an insulated suit. Fours years previous. In 1947, Harvey L. Williams of Connecticut filed a patent application for a “one piece, step in diving suit. In fact the earliest example of a waterproof diving suit was filed by Thomas Edgar in 1927. This was much more like a modern dry suit than a wetsuit.

Why Hugh Bradner deserves the praise? Is that he figured out that the cellular structure of neoprene. Makes it a superb wetsuit material. Like many inventors, he chose not to patent his idea. Wrongly believing that only a few hundred people might wear wetsuits. How wrong he was hey guys!

Breaking it all down

Why ocean water cools your body so quickly

Now unless you live in the tropics, the ocean will get very cold in the winter. In a cold, coastal country like the UK, the water can be a s low as 6-8 ℃ (43-46 ℉) In February – March, this is when the sea water is bitter. Entering the water when it is that cold without a wetsuit. You risk a life threatening condition called hypothermia. Where the inner core of your body gets so cold that it does not warm up again. It is very dangerous to swim in water this cold. Your heart beats irregular and you can die in a matter of minutes.

When you swim, there are far more water molecules surrounding your body. This is because water is a heavy, dense liquid. The water molecules are so much nearer to one another, so they can conduct heat more efficiently. This is why water carries heat energy away from your body around 25-40 times faster than air. Which is why it can be a warm sunny day, but when you get in the ocean you feel freezing.

Wetsuit Insulation

So your wetsuit if fitted correctly (we’ll get to that later) will let a thin layer of water in. Both your body and the water are pressed up a thin layer of neoprene. On the other side of the neoprene is icy cold water. Neoprene will insulate you from this cold water although it is not a 100% efficient insulator. Some body heat will pass through the neoprene and attempt to warm the water outside. As this happens it will cool you down in the process.

This is where thickness comes into play, simply put a 5mm wetsuit will be warmer than a 3mm wetsuit.

Wetsuit Construction

So a small amount of water will seep through many types of stitching/seams. Where the material comes together. For some types of suits this is acceptable. Summer 3mm wetsuits for example. Have flatlock stitching that actually allows a slow seepage. For summer wetsuits this is perfectly acceptable. The suit is more than efficient enough to keep the user warm in cool summer waters.

In winter conditions it is more important to keep the heat inside the suit. So we try to stop water seepage at the seams in several ways. Blind stitching is a method of stitching. Where the needle & thread does not go all the way through the material. So there is no needle hole for the water to go through. Firstly the panels of the wetsuit were all glued together. To stop water getting through at panel edges. Then the panels are blind stitched on both sides. This method is “Glued and double blind stitched”. This is a very popular method and works very well.

Surface Coating

Most wetsuits are made from what is termed double lined neoprene. This means that the neoprene rubber is laminated to a fabric, normally stretch nylon. This is to give it added durability and to allow it to be stitched together. This fabric is ideal for the functionality, construction and design of a wetsuit.


FAR Infrared Technology

Another further way to keep you warm in your suit is FAR infrared technology. Suits featuring mineral enriched fibers that capture your body heat. Then convert it to FAR infrared rays in order to keep you warm are the most common. A FAR infrared Ray is a spectrum of sunlight with a wavelength between 4-100 microns. NASA discovered that between 6-14 microns is capable of penetrating the human body. Raising the temperature while improving circulation & stimulating cell growth.

Benefits to the human body using FAR infrared technology are:

  • Heat penetrates deep into your core
  • Relieves joint pain & stiffness
  • Improves blood circulation
  • Provides warmth
  • Stimulates cell growth
  • Accelerates metabolism

Using this technology allows you to wear a thinner wetsuit in colder water. Increasing your flexibility. Being cold drains your energy and cuts time spent in the water. Normal wetsuits are only able to insulate & reduce heat loss. But these wetsuits have the capacity to generate heat.

Wetsuit Thickness

In short if warmth is your goal. when choosing a wetsuit, then the thickness of the neoprene is an important aspect. Wetsuit thickness is measured in millimeters. Represented with two to three numbers separated by a slash. The first number represents the thickness of neoprene in the torso area. The second represents the thickness in the extremities. Or just legs if there is a third number, if so then the third number represents the thickness in the arms.

The thicker neoprene is used for your torso to maintain your core body heat. Your core heat is extremely important to maintain in order to prevent hypothermia.

How Should A Wetsuit Fit?

Fit is a very important aspect to consider when buying a wetsuit. If your wetsuit does not fit properly. It will not allow you the mobility you need for your sport or be able to keep you warm.

A wetsuit should fit you like a second skin with no excessive bunching in the arms or legs or sagging in the back. It should fit tight to keep a thin layer of water between your suit and body. If your suit is loose in any way. An abundance of water will flush through, making the suit less effective at keeping you warm.

(consult brand specific charts for wetsuits for the best way to help find the correct wetsuit fit.)

Wetsuit Fit Checklist

  • After you have your wetsuit on there should be no excess room in the torso, crotch, shoulders or knees. A proper fitting wetsuit will be challenging to put on when dry. (Pro Tip: Keeping your socks on will allow your feet to slide in much easier!)
  • Once on, lift your arms over your head and stretch out your shoulders. This move should only be slightly restricting. If you feel a lot of pressure during this movement then the suit is too small.
  • You should be able to squat down and move your arms easily. (wetsuits above 5/4mm are inherently restrictive).

Types & Lengths of Wetsuits

There are several different types of wetsuits. That are best suited for different conditions. These different kinds of wetsuits range from tops or bottoms to full hooded suits.

Full Wetsuits

A full wetsuit covers your entire body. These suits can be found in various thicknesses made for different water temperatures. Full suits cover the entire body including legs & arms up to wrists & ankles.

Shorty Wetsuits / Springsuits

Springsuits, shorties & wetsuit shorts all feature thinner material and short arms & legs. These are primarily used in warmer water temperatures.

Long John/Jane Wetsuits

Exactly like a full suit but made with thinner neoprene. (usually 1.5 to 2mm) with no material at the arms again these are for warmer waters.

Wetsuit Tops

Tops or vests are made out of 05-2 mm neoprene that can be paired with board shorts or a bikini bottom. Primarily used for water sports in warmer areas. A Wetsuit vest can also be layered under a full suit for extra warmth in colder waters.

Wetsuit Bottoms

Neoprene pants, leggings or shorts primarily used in warmer water temperatures.

Temperature range for various wetsuit  Seals

Flatlock Wetsuit Stitching

Recommended for use in water that is above 62℃. Lies flat against your body, causing no discomfort yet may let in a little water.

Sealed Wetsuit Seams(Glued and Blindstitched)

Recommended for use in water that is 55℃ & higher. This suit has stitched panels that are glued and then blind stitched. This seam style will let in very little water

Sealed and Taped Wetsuit Seams(Glued, Blindstitched and 100% Taped)

Recommended for use in water that is 55℃ and below. This stitch is glued and then blindstitched. But it also contains interior seam taping. The interior taping will add durability. Reinforce the seam & prevent any water from seeping through.

Back Zip Wetsuits

One of the more classic solutions with the zipper going down the length of the spine with a long cord attached. so you can zip yourself in and out, which we all know can be a bit of a struggle. The advantage of the back zip is that, relative to the other styles, it is typically the easiest to enter and exit. This is quite important when you are trying to get into something that is skin tight.

The disadvantage is that water can get through the seams on the back zip. Freezing water down your back is not something you want. Also when bending forward, the suit will go taut in the back as the zipper lacks any give. Which may restrict movement.

Chest Zip Wetsuits

With the chest zip suit. You enter through a zippered cutout around the neck and you drop down into the suit through the neckline. Before pulling the neck cut over your head and zipping closed. Chest zips are definitely more trickier to enter & exit out of the two suits. However the chest zip is superior at keeping water from penetrating the suit. Through the neckline and seams. The chest zip may also be a more comfortable fit. once on with a snug neck & with the zipperless back yields a greater level of flexibility

By User:Yoruno – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=1708282

Zipperless Wetsuits

Found mainly on lightweight wetsuits and neoprene tops. These suits prioritize mobility over warmth. By eliminating the lack of flex found with zipped suits and stitching. This is a good solution if you have issues with mobility. The entry point for zipperless wetsuits can be found around the chest or neck area. Usually secured by a small zipper or Velcro.

Optional Features

  • An attached hood prevents cold water from flowing in through your wetsuit collar as you swim.
  • Kneepads are common, but you can also get elbow pads. Many suits have special anti-abrasion material on the shoulders and in the seat area.
  • Pre-shaped arms and legs (bent knees and elbows). Add comfort and prevent the neoprene from having to stretch so much as you move around. which will reduce wear and tear.
  • Pockets are good for carrying things like slates or keys. Pockets usually are placed on wetsuit thighs, calves or arms. Some suits also have interior key pockets.
  • Wrist and ankle seals cut water entry and circulation inside a wetsuit.
  • Ankle and wrist zippers make getting into and out of your wetsuit easier.
  • A spine pad fills in the channel made by your spine, which reduces water flow. Lumbar or kidney pads protect your lower back.

Wetsuit Thickness & Temperature Guide

These are general temperature guidelines. Many brands will provide their own temperature recommendations. That may differ slightly from those listed below.

Water Temperature Range (°F)Wetsuit ThicknessRecommended Wetsuit TypeSeal Type
65°- 75° 0.5mm-2/1mmTop / ShortyN/A
62°- 68°2mm – 3/2mm Springsuit / full suitFlatlock
58°- 63°3/2mm – 4/3mmFull suit & bootsSealed
52°- 58°4/3mm – 5/4/3mmFull suit, boots, gloves & hoodSealed and Taped
43°- 52°5/4mm – 5/4/3 mmFull suit, boots, gloves & hoodSealed and Taped
42° and below6/5mm +Full suit, boots, gloves & hoodSealed and Taped

How to Choose

  1. Think about where you plan to dive most to determine what style of wetsuit will work for you.
  2. Find the appropriate size and thickness based on some of the above information. Understand the style that will best suit your needs. Taking into account what you have learnt.
  3. Take your time. Pulling on a wetsuit  for the first time may take a little effort, so work your way through it without rushing. However if its a real struggle, perhaps you need a larger size.
  4. Evaluate the fit. A wetsuit should be snug, but not overly tight. There should be no big gaps anywhere.
  5. Narrow down your choice by fit and comfort. A wetsuit is an investment that should last for several years, so choose wisely.


So hopefully you have learnt some useful information. That will help you better understand wetsuits. Hopefully giving you some insight when choosing your own. As being comfortable when you scuba dive. Helps you to maximize the experience of an already enjoyable activity. So have fun choosing & dive safe.


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