What To Wear Under Board Shorts
tasc Performance

What To Wear Under Board Shorts

There are some questions every man wants to know the answer to but doesn’t really want to ask.

Whether or not to wear underwear beneath swimwear is one of those questions.

Thankfully, you don’t have to go around taking a survey from your friends and family. Our experts here at Tasc Performance have you covered with all the most important info.

Not all underwear is equal, and all board shorts aren’t the same, so a lot of factors can play into the decision. If you’re feeling a bit overwhelmed trying to figure it all out for yourself, just sit back and read on.

Today, we’re breaking down every consideration from top to bottom to help you decide whether underwear under your board shorts is right for you.

Do I Need To Wear Anything Under Board Shorts?

The first question to ask is whether underwear really goes with swim shorts at all. After all, many styles come with built-in liners, which surely must mean underwear doesn’t belong, right? Not necessarily.

Even with a built-in liner, there are a few downsides to be aware of if you’re thinking of going commando.

It Can Be Revealing

For starters, wearing board shorts without underwear can potentially be too revealing. Wet clothing tends to conform to the shapes beneath it and stick to the skin. Without underwear, this may result in a revealing silhouette around your underwear.

Most built-in liners don’t prevent revealing swimwear, but an actual pair of underwear is much more likely to stop the material of your board shorts from bearing anything behind the underwear’s profile.

It Can Cause Chafing

Another common problem of wearing board shorts without underwear is the potential for chafing.

Chafing is an uncomfortable and potentially dangerous condition that can occur after long periods of friction between your skin and certain fabrics, which becomes even worse when there is moisture involved.

If you’ve found chafing to be a problem while wearing board shorts in the past, or you simply want to avoid the issue altogether (which is definitely recommended), then wearing underwear beneath your board shorts is the way to go.

What Shouldn’t I Wear Under Board Shorts?

In the case that wearing underwear with swim shorts seems like the right choice for you, there are still some very important things to avoid.

Not all underwear is effective in supporting your needs while in the water, and different styles also have different pros and cons.

For example, while fitted underwear styles can certainly work, looser styles have the potential to cause chafing while you are in the water. 


Fabric is a major consideration in ensuring you choose underwear that will work for you in the water. Some fabrics work better in moisture than others—cotton is definitely one of the others.

The main reason cotton performs poorly in water is that the material is water absorbent. This causes a number of issues, not least of which is discomfort. Cotton becomes heavy on your body as you swim, and it takes much longer to dry once you exit the water than most other fabrics.

Cotton also tends to increase chafing while swimming rather than reduce it.

Further, when swimming in chemically treated water, cotton might even absorb the chemicals in the pool, which could be harmful to you and the state of the pool.

Not all cotton needs to be completely avoided. Organic cotton is an all-natural alternative that, when blended with powerful fabrics like bamboo, can be perfectly suitable for in-water use.

Is There Underwear Designed for Board Shorts?

So if you shouldn’t wear traditional cotton underwear beneath your board shorts, then what should you wear?

There are a number of options for those looking for a little more support and protection beneath their board shorts.

Built-In Liner

Built-in liners are a popular solution included in the design of many board shorts. There are pros and cons to this solution, but overall it is definitely viable for those who don’t want to wear an entirely separate layer with their swim shorts.

A high-quality liner can provide similar support and protection from chafing as a good pair of underwear. On the other hand, the fit of built-liners can be very particular and often makes it difficult to find the right pair for you. 

Liners can also grow uncomfortable over the course of a long day on the water or during high-intensity water activities such as surfing. In these cases, it’s definitely recommended to go with an actual pair of underwear up to the job.

Compression Shorts

Compression shorts are a popular choice when it comes to underwear under swimwear. Most compression shorts are made with synthetic fabrics, which are treated to be water-resistant.

Unfortunately, these chemical treatments come with other downsides to the environment and even potentially your health. Choosing compression shorts that don’t use chemical treatments can be a great solution to slip on under your swim shorts.

A pair of form-fitting boxer briefs using the right materials, such as bamboo, can also do the job as well. Consider a style like the Bambare Boxer Brief for an all-natural option that’s ready for any situation you throw its way.

Swim Briefs

While swim briefs are certainly more popular in some parts of the world than others, that doesn’t mean they don't have an alternative role to play, even in regions where they aren’t commonly worn as outer garments.

Swim briefs can make one of the best undergarments beneath board shorts for those who want more support. Since they’re specifically designed for swimming and water activities, you can rest assured they’ve got all the performance features and comfort you’ll need.

What’s the Most Important Thing To Look for in Surf Underwear?

No matter which style you go for, there are a number of all-important factors to look out for when choosing underwear for water activities.

Across all of these factors, fabric is fundamental. The fabric you choose for your clothes determines most of the essential features and even plays a role in the environmental impact of what you wear.

As we’ve seen, traditional cotton fabrics aren’t ideal for water activity and have downsides for regular use. Likewise, the chemical treatment of synthetic fibers can be detrimental to the environment and potentially to your health and safety.


Moisture-wicking may seem redundant for styles that you plan to swim in—it’s anything but.

Moisture-wicking is the capability of fabric to draw moisture from the skin and release it as vapor into the air. Typically, we think of moisture-wicking in the context of exercise and athletic training.

While moisture-wicking is certainly helpful in dealing with sweat, it’s got a big role to play in the water as well. Primarily, moisture-wicking keeps your clothes from absorbing water and becoming weighed down. 

It also stops chemicals or bacteria from water from getting absorbed into your clothes and causing long-term degradation of the material.

Quick Drying

When thinking about clothes to use in the water, we’d be remiss to forget how they function once we’re ready to leave water too.

Clothes that dry quickly are a huge benefit for most water-bound activities. 

Whether you’re heading from the pool to the restaurant or from the waves back to your beach chair, staying wet can cause any number of issues, from general discomfort and chafing to dangerously slippery floors and injury.

Choose fabrics like bamboo with water-resistant and quick-drying capabilities to keep your life in and out of the water separate.

4-Way Stretch

Range of movement is important for your time in the water, especially if you’re getting into something more intense like surfing or a game of water polo. 

Choose underwear with flexible fabric and serious stretch capabilities to ensure you’re unhindered.


The last thing you need during a long day in the water is extra weight on your body while you swim. 

Every bit matters, and a pair of underwear that is both lightweight and that does not absorb water can be key to making your swim as comfortable and enjoyable as possible.


Whether you’re looking for some extra support before you hit the waves or just trying to stay comfortable for a relaxing swim, there’s a lot to consider in what sort of undergarments (if any) might be right for you beneath your board shorts. 

Stick to Tasc performance for more guides from our experts to make decisions like this easier and more efficient than ever.


Chafing: Treatment, Prevention, and Causes | Healthline

Organic Cotton - An Overview | Science Direct

Toxicity of Synthetic Fibres & Health | Austin Publishing Group

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