How Thick Should a Triathlon Wetsuit Be? Why You Need (A New) One!


Many triathletes opt to compete in a triathlon that has a pool swim versus an open-water swim for their very first triathlon; though, a few will opt for one with an open-water swim. Even if you do opt for a pool swim for your first-ever triathlon, you will eventually make it to the open water.

Thus, regardless of where your very first/first-ever triathlon will be (was), the pool or open water, you may be wondering what the rules/regulations for wetsuits are when it comes to triathlons- particularly about their thickness. 

Though a wetsuit was once an optional piece of equipment for triathlon/the triathlete, nowadays it’s almost a required piece of equipment. And, sometimes, when the water temperatures are cold enough, it’s mandatory to wear one. 

Furthermore, USAT, IT, & WTC (Ironman) have rules about the thickness of wetsuits. Their rules state that wetsuits can be no more than 5mm thick (at any point on the wetsuit). Thus, one’s wetsuit for their triathlon(s)/triathlon event(s) will need to be 5mm or less in thickness at any given point on the wetsuit. 

Because the governing bodies for triathlon events do not allow wetsuits to exceed 5mm thickness, [most all] triathlon wetsuits, regardless of brand, are no more than 5mm thick (at any given point).

Most brands design their wetsuit(s) to have the thickest rubber/neoprene (equal to, or less than, 5mm) at the chest and front thigh areas and keep the shoulder areas thinner (2mm or less).

Each governing body- USA Triathlon (USAT), International Triathlon Union (ITU), and World Triathlon Corporation (WTC)- which includes Ironman- has its specific guidelines about water temperature(s) and wetsuits; however, they are pretty much all identical. 

  • Water temperatures less than 53 degrees Fahrenheit → event [typically] canceled 
  • Water temperatures above 84 degrees Fahrenheit → wetsuits [typically] prohibited/banned (i.e., one is NOT Allowed to wear a wetsuit; this is to prevent overheating) 
  • Water temperatures between 53- and 61-degrees Fahrenheit → wetsuits [typically] are mandatory for triathletes/swimmers 
  • Water temperatures between 61- and 84-degrees Fahrenheit → wetsuits are allowed, but not required; however, there are stipulations about wetsuits and eligibility for awards (so be aware of those and take them into consideration)

This design adds buoyancy at the heaviest points of the body (chest/torso and thighs) while allowing for a full range of motion and greater efficiency of the arms (i.e., greater flexibility and arm speed). (Source A)(Source B)(Source C)

As was said, these rules are pretty much identical amongst the main governing bodies for triathlons (USAT, ITU, and WTC/Ironman), but they can vary; so, while these provide some general guidelines, you will want to be sure to check the specific guidelines for your particular triathlon/triathlon event(s). 

The fit of one’s wetsuit is the most important thing when it comes to this valuable (and, as we can now see, very necessary) piece of equipment- a properly fitted wetsuit is key. One’s wetsuit should fit snuggly, like a glove or second skin, but allow them to breathe normally, with ease and have a full range of motion of the arms [and legs]

Speaking of gloves, on a side note, we recommend that you check out our post “Can You Wear Neoprene Gloves In A Triathlon? Pros, Cons & Foot Wear Option!

Not all wetsuits are triathlon-specific (i.e., not all wetsuits are created the same). Some wetsuits, such as those for diving or surfing, will not provide the buoyancy that a tri-specific wetsuit will. Rather, they will protect one from the elements of the environment/the water, but provide little to no buoyancy/buoyancy support.

Triathlon wetsuits, on the other hand, do typically provide some help with buoyancy/buoyancy support. Check out the one we use and recommend (Amazon link )


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What Is the Function / Benefit of A Triathlon Wetsuit ?

A triathlon wetsuit has three core functions: 

1. Buoyancy 

Its help with buoyancy can be good or bad, depending on your frame size and/or natural ability to float. For those that struggle to float and stay atop the water, this is a good thing because it will help you to float/put your body in an optimal position in the water.

For those that can float and do not struggle in this area, the buoyancy help can be negative as it could put one too high in the water- making propulsion more difficult. Additionally, it tends to help those that are lean more so than those that are thick/bulky. 

2. Warmth 

The material make-up (tiny closed-cell membranes/pockets of air) of the neoprene fabric and construction of the wetsuit itself lend to keeping the swimmer’s core insulated. Thus, keeping the swimmer warm while in cold(er) water(s). 

3. Streamlining 

The compression that a wetsuit provides and the slickness of the material both work to streamline a swimmer; thus, reducing drag. This increased streamline and drag reduction result in more efficient swimming and better times, generally speaking. 

What Wetsuit Do I Need for A Triathlon?

First and foremost, you will want to assure you have a wetsuit specific to the triathlon sport/competitive open-water swimming. While one could certainly use a wetsuit designed for another water sport (so long as it meets the event’s governing body’s rules and regulations) as a means of saving cost, it will not lend to optimal performance and protection like a wetsuit designed specifically for the triathlon sport/competitive open-water swimming would. 

For more on this you can check out our post: Triathlon Vs Surfing Vs Diving Wetsuit; Can They All Be Used in Triathlon? How To Pick One

That said, wetsuits for triathlon come in a few different styles. The two most common are sleeveless and long(full)-sleeve. Which type one needs specifically- long(full)-sleeve or sleeveless- depends on a few factors. Namely, the water temperatures and type of event(s). 

If you are swimming in warmer water (and 1. wetsuits are allowed for your event 2. you prefer swimming in a wetsuit over not), then the sleeveless or a thinner (3mm or less) style triathlon wetsuit (long(full)- or short-sleeve) is going to be your best choice. 

However, if you are swimming in cold water, then you will want to opt for a thicker (i.e., a wetsuit with 5mm thick panels in the chest and thigh areas, at a minimum), long(full)-sleeve triathlon wetsuit. 

It is also worth noting that long(full)-sleeve triathlon wetsuits are [generally] more efficient overall. The long(full)-sleeve wetsuit provides even more buoyancy and greatly reduces drag- thus, making one more efficient in the water [overall].

A sleeveless style, however, allows more water in. This admittance of additional water creates drag which, ultimately, is a big factor in slowing one down and renders one less efficient.  But, again, it will ultimately, in addition to personal preference, depend on the water temperature(s) and event(s) as to what style of wetsuit you need. (Source A)(Source B)(Source C)

If you will wear a wetsuit for any reason, we highly recommend that you check our post: How To Treat Wetsuit Chafing Effectively? Prevention and Helpful Tips!

How Much Does a Wetsuit Help in A Triathlon?

Scientific studies show that a wetsuit can have a pretty significant (and positive) effect on swim performance. One study showed that those that wore a full(long)-sleeve wetsuit were able to go 5 to 10 seconds faster per 100 meters (i.e. they swim/go faster in a wetsuit than when not in one, over a distance of 100 meters)- this equates to a roughly 3 to 7 percent improvement of swimming speed (all from one piece of equipment- the wetsuit). 

Furthermore, studies have shown that wetsuits have a greater impact on short distance (i.e., 400 meters or less) events than long-distance (i.e., 400-1500+ meters) events. And, they tend to help those that are lean more so than those that are thick/ bulky. This is because of buoyancy- both one’s natural buoyance (or, lack thereof) and the buoyancy assistance a wetsuit provides. 

Also, wetsuits reduce drag- the friction between a swimmer’s body and the water. Studies have shown a reduction in drag of about 14 percent  

One’s ability and practices will also factor into just how much a wetsuit can/will help. One that is a high-caliber swimmer and/or goes the extra length of shaving their body hair, may not see much improvement with a wetsuit. But- for those not going to quite those lengths and/or that may not be at that caliber of swimming- Yes! A wetsuit can [pretty significantly] help you/your performance in a triathlon event. (Source A)(Source B)

Do Wetsuits Lose Buoyancy? (Should You Get a New One )

Yes, over time a wetsuit will lose its buoyancy. Despite what some may say in contrast, a wetsuit will, in fact, lose its buoyancy over time. Kind of like a tire full of air- over time, whether the tire is used or sits idle, it will [eventually] lose air (deflate). It’s facts (or, science- however you see it). 

Neoprene (a wetsuit) is made up of tiny closed-cell membranes (air pockets). Over time those air pockets (closed-cell membranes) become compressed and lose their encapsulated air- thus, they shrink (deflate), and the wetsuit loses buoyancy (much like the tire that loses air/deflates over time…). So, yes, over time (even with proper care) a wetsuit can (and most likely will) lose its buoyancy. 

Also, a wetsuit loses buoyancy the deeper one goes

At roughly 33 feet, a wetsuit loses about half its buoyancy. At roughly 66 feet it loses about two-thirds of its buoyancy. And, at roughly 100 feet it loses all its buoyancy- thus, at 100 feet the wetsuit may protect against the elements of the environment/the water, but it has no [positive] effect on buoyancy. 

With proper care of your wetsuit, you can increase its longevity, but, ultimately, over time, [as it was stated previously] it will lose its buoyancy (i.e., ultimately, it will need to be replaced). (Source)

Melissa Frank

My passion, outside of animals, is helping people and adding value to their lives…I strive to leave the world a little better than I woke to it each day. The first part of my career, for a total of about 15 years, was spent in the public safety field as a Volunteer Firefighter/EMT-B and 9-1-1 Operator. In 2019 I obtained my personal trainer certification (ACE certified) as well as many group fitness certifications and certification as a Corrective Exercise Specialist.

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