What to Wear Under Swim Trunks?

what to wear under swim trunks

Most of us wear underwear with regular shorts, but what about swim trunks or board shorts? Some swimwear look so good that you’d want to wear them like regular shorts, which begs the question: do you wear underwear with them or not?

This is a question that perplexes many men (and even women) since you don’t have to wear anything under your swim trunks, yet many guys still do. Who is right, and who is wrong? The answer is that it’s all personal preference – there are pros and cons to wearing undergarments under swim trunks .

As for the purpose of this article, we are not trying to convince you to go in one direction or another. Your reasons for wearing underwear under your swim trunks (or not) are your own. However, we would like to discuss this topic in more depth so that you can see both sides of the argument.

Why wear anything underneath at all?

The reason why the majority of recommendations are that you don’t need to wear anything under your swim trunks is because most of them come with an inner mesh lining, also called netting . As with anything, some people love it and some hate it. If you hate it, board shorts typically don’t have any netting inside.

Mesh lining is made from polyester and has many holes in it. This keeps the material lightweight and allows water to pass through while absorbing very little of it, ensuring that it dries very quickly. The netting also keeps the inner fabric of the swim trunks away from your skin, reducing the likelihood of chafing, while offering support for your private part.

That said, not all swim trunks come with mesh liners. Also, some men find the netting to be rough and itchy, exacerbating the problem it is supposed to solve. This is less of a problem if you buy a higher quality pair of swim trunks with mesh liners made from softer polyester.

On the other hand, many men praise the lining since they don’t want to wear underwear with their swim trunks. Exposing your nice underwear to chlorine or saltwater can cause the waistband to get damaged and the color to fade.

Plus, cotton boxers absorb water like nobody’s business and dry very slowly. Furthermore, when they are wet they increase in friction, resulting in chafing. It’s an overall losing combination.

With that said, if you dislike both the mesh liner and wearing cotton boxers, then what options are you left with? What would be the appropriate undergarments to wear under swim trunks without mesh lining, such as board shorts?

What to wear under swim trunks and board shorts


If your swim trunks or board shorts don’t have mesh lining inside, the most common option is to simply wear your boxers underneath. This might seem like a suitable option at first when you’re still dry, however this feeling won’t last very long once you’re in the water.

Boxers are typically made from cotton, and cotton will absorb a lot of water. This not only weighs you down, but it will feel like you’re wearing a soggy diaper.

Plus, boxers are not designed to be repeatedly exposed to saltwater, chlorine, or any other chemical that is found in pool water. You will find your boxers will start to fade and get worn down very quickly. The waistband will become loose and not fit you as snug as it used to. Not great things to happen to your favorite pair of boxers.

To make matters worse, your boxers can actually be an impediment to your enjoyment. The reason why mesh lining is so effective is because it does not absorb water and dries quickly. Boxers absorb plenty of water and therefore will not dry quickly.

Furthermore, if you were wearing boxers to try to reduce chafing, you might be adding to it with wet boxers. When soaked, the friction increases and can rub against your inner thighs much in the same way that your swim trunks can.

Overall, boxers are very hit-or-miss. Some people find it helps them reduce chafing and feel protected, whereas most would probably find it to be an impediment.

Compression shorts

A much better undergarment to wear than boxers are compression shorts. Compression shorts are typically used by athletes while working out, but they can double as swimwear in a pinch. The compression they provide is thought to improve blood circulation and protect muscles from damage, but that’s not why we are wearing them in this context.

Due to how snug they fit, they can add great support and protection while you’re in the water. They are also moisture-wicking to help you dry faster out of the water.

What many guys love about compression shorts is how long they are. Designed to reach all the way down to your knees, you can be sure that they will prevent chafing by adding a layer of protection between your skin and the swim trunks or board shorts.

Swim briefs (Speedos)

If you’re not comfortable wearing swim briefs, a.k.a. Speedos normally, then you can wear them under your swim trunks.

Swim briefs are typically worn by competitive swimmers that want as little drag as possible in the water. This makes it a great option as an undergarment because it won’t absorb much water, allowing it to dry quickly.

Furthermore, Speedos are designed to be worn in the water, so you’re not sacrificing a pair of boxers or compression shorts. That said, they don’t offer nearly as much support as compression shorts, but they still keep things in place.

A one piece swimsuit

If you’re a girl and feel that one piece swimsuits reveal too much of your legs, then an easy solution is to simply wear board shorts over your one piece swimsuit. Now you can look more modest, get more UV protection, and possibly improve your outfit. Not bad.

Just go commando (wear nothing)

If your swim trunks are comfortable enough, you don’t need to wear anything at all under your board shorts or swim trunks. The obvious advantage of this is that it’s the most liberating and it’s also the most convenient.

Without another article of clothing on, your shorts will dry the fastest and you will be weighed down the least since no water is being absorbed into extra material. Assuming your shorts fit you properly, you shouldn’t have a problem with itches, rashes, things hanging loose and accidentally exposing yourself.

The downside of going commando with unlined shorts is that if the shorts are low quality or ill-fitting, you could experience some discomfort and accidental exposure. When you forgo your undergarments, you need to be sure that your swim trunks fit you well both wet and dry.

Also, be wary of board shorts that are brighter in color and made with thin materials; when wet, they could become see-through and you don’t want to be labeled as a voyeur and a pervert. Testing your shorts privately in anticipation of a wardrobe malfunction can help you prevent an awkward situation the next time you’re at the beach.

Parting words

While you don’t need to wear anything under your swim trunks if they come with a mesh liner, not all swim trunks come with netting and perhaps you just feel more comfortable wearing something underneath your swim trunks.

If so, then you can wear your boxers, swim briefs (Speedos), or compression shorts. Boxers are arguably the worst option of the bunch, followed by compression shorts and Speedos.

Speedos are actually designed to be in the water, so you don’t feel like you’re sacrificing a nice pair of boxers or compression shorts. They also dry the fastest but they don’t offer as much support as compression shorts.

Ideally, you should just get a high quality pair of swim trunks with softer polyester liner inside so you don’t need to wear anything underneath and you can still feel comfortable.