Wetsuit Thickness Guide
Mar 01, 2023
Finding the right wetsuit for your upcoming aquatic adventure or competition helps ensure the safest and most comfortable swimming conditions. Picking the appropriate thickness is vital to retaining body heat in cold water, reducing fatigue, and maintaining dexterity.
How Do Wetsuits Work?
Wetsuits aren't designed to keep the covered areas of your skin dry. They’re supposed to let in some water and trap it in the very thin gap between your skin and the fabric. The water is part of the insulation process.
Wetsuits are made of synthetic rubber called neoprene, which is a closed-cell material that's filled with small bubbles of nitrogen gas. The warmer temperature coming from your body transfers to that thin layer of water that has gone inside the wetsuit and stays there while you're out at sea. Nitrogen's very limited thermal conductivity compared to water prevents heat from being released from your wetsuit.
Wetsuit Thickness Guide
Wetsuit thickness is expressed in millimeters. The higher the number, the thicker and warmer the wetsuit will be.
Brands may use either two (3/2mm) or three (5/4/3) numbers for the measurement. If there are two numbers, the first number stands for the thickness of the fabric in the torso area, while the second number is the thickness for the arms and legs. If there are three numbers, the first number will correspond to the torso. The second number will be for the legs, and the last number represents the thickness for the arms. There's just one measurement or neoprene thickness for the fabric in more basic wetsuits.
You need to consider several factors when deciding the right wetsuit thickness for you:
- Personal cold sensitivity (whether you easily get chilly or you tend to be warm or easily overheat) and body type (amount of your body fat and skin thickness)
- Water activity (contact with the water varies for snorkeling, standup paddleboarding, or surfing)
- Water conditions (flat water or rough waters)
- Local water temperature
- Local wind conditions or air temperature (including wind chill—the wind from the north is typically colder than the wind from the south)
Buell’s Wetsuit Water Temperature Guide
Buell's wetsuit water temperature guide can help you decide when you're considering what wetsuit thickness and type will best match the following water temperatures:
- Over 80°F/Over 26°C: short or long-sleeved rash guards
- 71°F to 79°F/21°C to 25°C: 1mm short or long-sleeved wetsuit top
- 65°F to 70°F/18°C to 20°C: 2mm spring suit or long-sleeved shorty wetsuit
- 55°F to 64°F/12°C to 17°C: 3/2mm full suit with booties
- 48°F to 54°F/8°C to 11°C: 4/3mm full wetsuit with booties and five-finger gloves
- 40°F to 47°F/4°C to 7°C: 5/4mm full wetsuit with booties, five-finger gloves, and hood
- Below 39°F/Below 3°C: 6/5/4mm full wetsuit with booties, mittens, and hood
How Should a Wetsuit Fit?
A proper-fitting wetsuit is snug with a little pressure—no folds or wrinkles. It should feel like a second skin but also fits tight enough that it takes a little while to put it on. At the same time, it shouldn't restrict your range of motion or cut off your circulation. If you tug gently on the wetsuit's lower back, and there's no give, then you've got a good fit. Like swimsuits, the wetsuit loosens up and will feel more comfortable on you when it gets wet.
The area around the neck should be high and fitted to prevent water from flooding your wetsuit. Too much water inside will slow down your movement.
Butt and crotch
The butt and crotch areas shouldn't be too loose. There also shouldn't be any sagging at the knees. A wetsuit with a good fit allows you to squat down.
Arms and legs
For full-length wetsuits, the sleeves should end at the wrist bone, while the legs should fall above the ankle bone. You should be able to put your finger in the seals on the neck, wrists, and ankles—but nothing wider than that. If you feel a lot of pressure while lifting your arms over your head and stretching out your shoulders, your wetsuit is likely too small for you.
Wetsuit makers typically make allowance for the arms and legs. So don't be surprised if your wetsuit's arm and leg parts are long—you can trim them to match your length.
You'll also normally find extra neoprene in the wetsuit's armpit area, referred to as the raglan gusset. This is the manufacturing standard for all wetsuits in the market as most buyers are surfers, who paddle 90% of their time in the water. The gusset widens the wearer's range of motion, preventing fatigue.
Refer to the Size Chart
The best way to choose the right size is to compare your chest, waist, height, and weight measurements to your wetsuit brand’s size chart. If you're between sizes, check the measurements for your chest and waist to help narrow down your choice. But if you can shop in-store, it's better to try on both sizes.
6 Different Types of Wetsuit Construction
A wetsuit consists of several neoprene fabric pieces that are joined together through a variety of stitching and sealing techniques. Here are the common methods used:
One neoprene panel edge is laid over the other, and a machine needle stitches through them at the seams. It lies flat on your body, but the process creates many holes. As a result, wetsuits with flatlock stitching are best for summer use or in warmer water temperatures (over 62F or 17C).
Like flatlocks, overlock seams are also stitched together. However, the edges are rolled together before they're sewn at the tips. This creates a bulge on the wetsuit's interior, which can result in chafing.
Glued and blind-stitched seams
Neoprene fabric pieces are first glued together at the seams before being stitched together, creating a more watertight seam. This type of stitching doesn't produce holes as thread only goes halfway through the material. As a result, water entry is kept to a minimum. You can use them in 55C waters and below.
Partially taped or spot-taped seams
Tape is glued (heat-welding) on stitched areas located in the critical parts of a wetsuit's interior, particularly spots that undergo high impact such as the knees.
Fully taped seams
A wetsuit with fully taped seams features taping in all areas where the fabric had been stitched. The tape covers the holes created during the stitching process. You'll find these seam seals on some mid-range and many high-end suits.
Also called liquid-taped seams, this type of wetsuit construction is the most watertight as liquid rubber or silicon-based urethane is used to join the seams. Most high-end suits feature fluid-sealed seams.
A wetsuit's entry system refers to the entry point of that outfit. There are four types:
Back zipper wetsuits
The vertical back zipper, which is found in most wetsuits, offers the easiest entry. It offers a wide body hole that's easy to step into. The zipper pull is typically long or has a cord that lets you zip and unzip yourself. It also normally features a higher and tighter seal around the neck. Back zips usually last longer because you do less pulling to put on the wetsuit and take it off.
The downside of wetsuits with back zippers is that they’re generally made of more individual neoprene pieces. This means more seams, which can reduce your flexibility.
Front or chest zip wetsuits
Most surfers prefer the front zip, which features a zipper that’s either straight across the chest or angled slightly. Chest zip wetsuits can include a snap button that locks the zipper pull in place or a cinch cord, which tightens the entry and makes it less prone to flushing.
While it's a trickier entry point compared to the back zip, a chest zip prevents too much water from coming inside your wetsuit. Some users also find wetsuits with chest zippers to be less tight around the neck, shoulders, and back.
Wetsuit tops and thinner wetsuits that are primarily designed for mobility instead of warmth are usually zipper-free. But there are also high-end performance suits with ultra-stretchy neoprene that are zipperless.
The main advantage of zip-free wetsuits is that you won't have to worry about zipper breakage.
Mod and mutant entry
Wetsuits with this type of "entry" feature a front and back zipper but don't actually provide two entry points. However, it gives you the option to use it as either a plain chest zipper suit or a "mutated" hooded full suit (the hood is detachable).
Types of Wetsuits
A full suit, also referred to as a steamer, provides full-body coverage—your torso, arms, and legs, up to your wrists and ankles. Some brands offer steamers with short sleeves.
Shorty wetsuits (also referred to as springsuits)
As the name suggests, shorty wetsuits have short arm and leg coverage. Usually made of thinner material, a shorty style is great for warmer water temperatures or as a summer wetsuit.
Short John/Jane wetsuits
This wetsuit type features sleeveless tops and short legs. However, the short johns of some wetsuit brands can have short legs and long sleeves.
Long John/Jane wetsuits
Long John/Jane wetsuits don't have any sleeves but offer full leg coverage.
Like short Johns and Janes, they offer a full range of motion and are best for warm water surfing, kayaking, water aerobics, and other water sport focusing on upper body movement.
Wetsuit tops cover your torso and arms and are normally up to 2mm thick. They're designed for wear as stand-alone garments or second layer (wetsuit vests and jackets) during times in the summer when it's chilly (early morning and windy weather). They work best for surface water sports, such as wakeboarding, jet skiing, and stand-up paddling.
You can pair off a wetsuit top with board shorts or a bikini bottom.
Wetsuit bottoms include wetsuit shorts, pants, and leggings. Wetsuit shorts can be worn alone or under your wetsuit for extra warmth and protection, especially in colder water.
Rashguards (also called rashies) are lycra and UV ray-blocking swimwear that are normally worn under wetsuits to reduce chest or underarm rash from paddling. They also make a good first layer in cool to cold air and water temperature.
Wetsuit caps and hoods
When you're in a cold environment, your head is one of the areas where you lose the most heat from your body. Thus, wearing a wetsuit cap or hood can improve your body heat retention. It's a great defense against brain freeze, which can be set off by cold water temperatures, especially during the colder months.
You may need a wetsuit cap or hood if your head gets cold in the water fast. It can also protect you from earaches or so-called "surfer's ear" due to overexposure to wind chill and cold water.
There are stand-alone hoods and head covers that are built-in to wetsuit tops. Hooded wetsuits normally have thicker neoprene.
Warm water hoodies cover less of your face and have lower neoprene thickness compared to cold water hoodies. Hoods for colder waters also typically have long bibs that need to be tucked inside the wetsuit.
Warm hands aren't just necessary for you to stay in motion in water. You also need them to be able to set up and pack down your equipment as well as to do safety procedures. Wetsuit gloves can warm your fingers and prevent them from growing numb due to the cold. They also protect your hands from sharp underwater debris and rocks.
Gloves are worn under the wetsuit to prevent them from filling up with water. They come in different variations: five fingers, lobster claws, three fingers, and mittens.
Also called wetsuit booties, this footwear type will warm your feet in the cold to freezing water. Booties for warmer water have thinner neoprene. Wetsuit boots can also keep the soles of your feet safe from rocks and other prickly objects.
They come in two styles. Round-toe booties cover all the toes like a regular shoe. Meanwhile, split-toe booties have one chamber for the big toe and another for the rest. Surfers prefer the split-toe type, as they give a better feel of the board, particularly during strapless riding.