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Have you ever wondered whether swimsuits and underwear are actually the same thing? I mean, they cover the same body parts and their designs aren’t so different. Heck, you can even wear a swimsuit as an underwear. And yet, people freak out on the idea of wearing an underwear for swimming. Why the heck is that? In this post is the answer.

So can you really go swimming in your underwear? Some underwear can perfectly pass for swimsuits. Some are obviously a no-no the moment you set eyes on them. The general indicator (but not always) is the fabric opacity. If the fabric is see-through when wet, like most underwear are, then it’s a good idea NOT to go swimming in it.

If it isn’t see-through, then it’s probably okay to swim in it but there are exceptions.

Note: The keyword here is “okay“. Meaning, only substitute a swimwear with an underwear if you have no choice— like having an impromptu trip to the beach/ lake/ pool in the middle of nowhere and you have no swimsuit with you.

Remember, a swimsuit functions better as a swimsuit than an underwear ever can.

Aside from the fabric’s opacity, here are things you should think about before going swimming in your underwear.

What underwear designs are okay to wear as swimwear?

Can You Go Swimming in Your Underwear?
This simple design is found in both underwear and swimsuits. Hence, it’s perfectly okay to wear this pair for swimming.

If your underwear features a classic style— devoid of lacy embellishments and ribbony details which are typical of lingerie— then it’s perfectly safe to wear it for swimming. In fact, no one would probably even notice.

However, if your underwear is lacy and adorned with embroidery, then wearing in a public beach/ pool is not a good idea. People will likely notice and stare.

Why it’s inappropriate to wear a lacy underwear for swimming

Unless you couldn’t care less about the occasional odd stares you’ll likely get, skip this rule.

is push up bra good for small breasts
You don’t wanna wear this lacy bra as a swimsuit if you don’t want people staring at you.

This begs the question, “why?”. Why is it inappropriate to wear a lacy underwear as a swimsuit? As you can see, this lacy bra basically covers the same area as a swimwear top would. But why can’t you wear this in public?

The issue, in this case, is not the coverage but the fabric. Lacy fabrics are fabrics usually associated with sensuality, lingerie, and sexy time. You rarely (if at all) see them in a public beach/ pool.

If someone saw you wearing a lacy underwear in a public beach/ pool right now, the initial reaction would be the nagging feeling that something in your outfit is amiss.

Then dawns the realization that you’re wearing a lace. Lace equals lingerie equals sexy time. Then the discreet question, “Is this woman wearing a lingerie for swimming?!

Of course, this sounds ridiculous. And women are probably the only ones who’ll likely notice this tiny detail.

But that’s humans for you. And there goes the explanation as to why some underwear are okay to swim in and some are better worn… under.

Thread strength must be strong enough.

Most underwear threads don’t have a reliable hold once soaked wet. Hence, it’s extremely important to gauge the strength of your undies’ thread before going for a swim.

A good rule of thumb is: If you aren’t sure about it, don’t swim in it.

One strong wave from the sea is all it takes to end up in an embarrassing situation you’ll never forget for the rest of your life.

Your underwear’s fabric matters A LOT.

what is the best fabric for swimwear

Polyester fabric is the most okay fabric to swim in because it repels water and dries quickly. It’s also highly durable so it can withstand the assault of the sun, chlorine, and saltwater.

Do not wear 100% cotton underwear as your swimsuit!

There are several reasons why cotton isn’t allowed in public pools:

First, it sheds lints when soaked. These lints then accumulate in pool filters which just isn’t fun to deal with.

Second, cotton tends to hold detergents, germs, and bacteria in it, which can be released into the water, change the water chemistry, and even cause sickness. Not fun either.

Lastly, cotton absorbs a lot of water so count on it to create a drag while swimming. If you’re not swimming in the pool though, this is probably manageable. Still, I wouldn’t recommend it.

If you decide that you do need a swimwear, here’s an article, I’ve written for you discussing the topic: What is the Best Fabric for Swimwear? Explained.

Be prepared for the possible damage

The damage of wearing your underwear as a swimwear alone isn’t worth it. Underwear fabrics are different from those of swimsuits. They’re meant to serve a different purpose— to be soft and delicate. Not to be abrasion and chlorine-resistant.

True, a polyester underwear may be strong enough. But it’s certainly less stronger than a polyester swimwear.

Why waste a perfectly good pair of underwear when you can snag a $5 bikini from the nearest Walmart sale rack? That said, only swim in your undies if you have to.

And when you do, wash them immediately with freshwater and detergent. Or better, with a solution like Swimsuit Wash Chlorine Removal (#ad). These types of solutions were specifically concocted to remove residual chlorine and salt that a laundry detergent can’t.


Things that make an underwear suitable as a swimwear substitute:

  • It needs to be opaque when wet. Unfortunately, underwear aren’t made for swimming so a lot of them are going to be transparent.
  • Avoid wearing white. White tends to be see-through.
  • Lacy underwear worn as swimsuits will likely raise eyebrows and invite odd stares. Classic, simple, unembellished underwear, however, can pass as swimsuits as long as they’re opaque.
  • Only wear an underwear for swimming if you have no other option. Remember, there are several reasons why underwear is called underwear and swimwear is called swimwear. Marketing ploy is not one of them.

And that’s a wrap!

Want look and feel like a million dollars in your swimsuit? Here are the styling hacks you should know about based on your body type.

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  1. You say “Unfortunately, swimsuits aren’t made for swimming” presumably that should be “underwear”?

    You also say “Then dawns the realization that you’re wearing a lace. Lace equals lingerie equals sexy time. Then the discreet question, “Is this woman wearing a lingerie for swimming?!“
    Of course, this sounds ridiculous. And women are probably the only ones who’ll likely notice this tiny detail. ”

    I assure you we men WILL notice. And approve.

  2. Darcie S. says:

    You missed one of the most important “intangibles” of swimming in your bra and panties. It’s just a little “naughty” and that makes it fun. Some of my most fun times in the water have been stripping down to my undies with my hubby for a swim at a “swimming hole” we discovered during our travels.

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