What to Wear Under a Wetsuit for Triathlon Swimming

Navigating the world of triathlon swimming is not just about mastering the strokes and building stamina. It also involves understanding the nuances of what to wear for optimal performance, comfort, and safety. 

One of the frequently asked questions by budding triathletes and even some seasoned ones is, “What do I wear under my wetsuit?” The short answer: a properly fitting swimsuit or triathlon-specific apparel is your best bet. 

However, the choices you make in this seemingly small detail can significantly affect your race experience. From chafing issues to temperature regulation and transition ease, the right undergarment can make or break your swim. 

With years of triathlon experience under our belt, we’re here to guide you through this crucial decision, ensuring you hit the water confidently, comfortably, and with a competitive edge. 

Whether you’re a seasoned triathlete or gearing up for your first race, read on to learn how to pick the right under-wetsuit clothes.

Importance of Choosing the Right Undergarments for Triathlon Swimming

Wearing the right clothes under your wetsuit for triathlon swimming is important for several reasons.

Prevent Chafing and Discomfort

The proper undergarments can prevent chafing and discomfort during the swim, bike, and run portions of the race. They can also provide additional insulation, helping to maintain your body temperature in colder water.

Improve Performance and Efficiency

The right clothes under your wetsuit can improve your performance and efficiency. They can reduce drag in the water, making you swim faster and smoother. They can also help you transition faster, saving you valuable time and energy.

Enhance Comfort and Confidence

Wearing the correct clothing under your wetsuit can increase your comfort and boost your confidence. It ensures a good fit, prevents any unexpected exposure, and maintains your look. Moreover, feeling and looking good can elevate your morale and motivation.

Suitable Options To Wear Under Wetsuit for Triathlon:

There are many options for what to wear under your wetsuit for triathlon swimming. Here are some of the most common ones:

Triathlon Suit

A triathlon suit is a one-piece garment that covers your torso and legs. It is designed to be worn for all three disciplines of a triathlon: swimming, biking, and running. It has a built-in pad for cycling comfort and pockets for storing nutrition. You can wear it under your wetsuit for swimming and then transition to biking and running without changing clothes.


Designed to enhance your swimming speed by reducing water drag, a swim skin is a form-fitting garment that covers your torso and legs. It’s crafted from hydrophobic materials, ensuring quick drying and water repellence. Ideal for warm water conditions or non-wetsuit swims, the swim skin can be conveniently worn over your or regular undergarments and removed after your swim.

Tech Shirt

A tech shirt is a snug shirt designed for the upper body. Made of synthetic materials, it effectively wicks away sweat, ensuring you stay cool and dry. This shirt is an ideal choice for added warmth and comfort beneath your wetsuit. You can pair it with your triathlon suit or underwear and comfortably continue wearing it for biking and running.


Underwear is the most basic option for what to wear under your wetsuit for triathlon swimming. You can choose any underwear that fits well and does not chafe. Some triathletes prefer seamless underwear or compression shorts for extra support and comfort. Others opt for swim briefs or bikinis for minimal coverage and drag.

Should You Go Commando?

Some triathletes choose to wear nothing under their wetsuits, often referred to as “going commando.” While this approach can reduce drag and chafing, there are important factors to consider:

Lack of coverage/modesty

Going commando means exposing yourself when you take off your wetsuit in transition or after the race. If you are not comfortable with this, you may want to wear something underneath.

Increased risk of suit malfunction

Going commando also means risking a wardrobe malfunction if your wetsuit rips or tears during the race. If this happens, you may end up showing more than you intended.

Less warmth for susceptible extremities

Going commando also means losing some warmth for your extremities, like your hands and feet. Wearing a thin base layer or tech shirt under your wetsuit can help retain some heat and prevent hypothermia.

If you want to go commando, apply anti-chafe balm on the groin area. Also, consider a modesty liner for your triathlon suit if you choose this option.

Test It Out Before Race Day

Don’t wait for race day to test the clothes you’ll wear under your wetsuit. Test them during training swims to spot any chafing or restrictions in your stroke. If needed, make adjustments, such as using an anti-chafe balm or altering the alignment of your suit. 

To prepare for race day, simulate the conditions by swimming in your wetsuit and selecting undergarments for the anticipated duration. This helps identify any comfort issues in advance.

How to Test Under-Wetsuit Clothes Before Race Day

Here are some steps to follow:

  • Choose your under-wetsuit clothes based on the water temperature, the race distance, and your personal preference.
  • Put on your under-wetsuit clothes and then put on your wetsuit over them.
  • Swim in open water or in a pool with similar conditions as the race venue.
  • Pay attention to how you feel during the swim: are you warm enough? Are you comfortable? Do you have any chafing or rubbing?
  • After the swim, take off your wetsuit and check your skin for any redness or irritation.
  • If you have any problems, try a different option or make some adjustments.
  • Repeat the process until you find the best combination of under-wetsuit clothes for you.


Choosing the right clothing to wear under your wetsuit for triathlon swimming is crucial for your overall performance and comfort. The correct undergarments can prevent chafing and discomfort, enhance your efficiency in the water, and ensure a swift transition between race segments.

Now, equipped with this knowledge, take the time to find the best option for you and make your next triathlon experience as comfortable and efficient as possible. Don’t forget to test your gear before the big day and dive into your race with confidence!

What do you wear under your wetsuit for triathlon swimming? Share your experience and tips in the comments below!

Frequently Asked Questions

Why is it essential to consider what’s worn under a wetsuit during triathlon swimming?

It ensures comfort, prevents chafing, and improves performance in the water.

Can wearing the wrong attire under a wetsuit negatively impact a triathlete’s speed?

Yes, improper attire can cause drag, reducing swimming efficiency.

Are there specific materials recommended for undergarments during triathlon swimming?

Hydrophobic materials that repel water and dry quickly are often preferred.

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