Do Swimsuits Get Bigger or Smaller in Water?

do swimsuits get bigger or smaller in water

Here’s a common scenario: you buy a swimsuit that is true to your size. It seems to fit well when it is dry, but problems start to arise as soon as you get into the water. For example, you may have noticed that your swimsuit sags a lot when wet. This increases drag in the water, which is not good if you are a competitive swimmer swimming laps.

Even as a casual beach or pool goer who prioritizes good looks over functional performance, a saggy swimsuit fails in that regard as well. It can get so bad to the point where the swimsuit can fail to cover up your private bits, and that is when the swimsuit has failed catastrophically.

Essentially, you might have noticed that the swimsuit expands when wet. Why do swimsuits get bigger in the water? And do they ever get smaller?

Typically, swimsuits will get bigger when wet because the materials are stretchy and they get stretched out when you’re moving around in the water. This is completely normal. For this reason, it’s generally a good idea to size down or buy true to size at most, but don’t size up. At some point, all swimsuits will naturally get stretched out, but this can take months or years.

Conversely, some people have found that their swimsuit fits much tighter since the last time they wore it. That has nothing to do with the pool or beach water, but most likely has to do with the way you washed it or dried it last time. Heat will cause swimsuits to shrink, so if you used hot water to wash it or you put it in the dryer or ironed it, then the elastic materials likely shrank.

If you read on, we will discuss the most common reasons why swimsuits get bigger in the water as well as why a swimsuit might feel tighter than the last time you wore it.

Materials used

As with other sportswear, swimwear specifically is made with a blend of fabrics that differentiate them from other clothes. For swimsuits, these materials must be porous and stretchy in order to be comfortable. The goal here is to cover you up without restricting your movements and to absorb as little water as possible.

To achieve this, the most commonly used fabrics in swimwear are nylon and polyester which satisfies the aforementioned requirements. Some other popular materials are lycra and spandex. Look at your swimsuit tag, and you will see that your swimsuit is made of some kind of blend of these materials.

What do these materials have in common that is pertinent to this article? They can all stretch a lot and will stretch more when wet. They will also all shrink when exposed to heat. Thus, their elasticity is very similar so you need to be very careful when washing and drying them.

How to retain your swimsuit shape

Even though it’s normal for swimsuits to stretch out over time, there are still ways for your swimsuit to last longer. After all, it’s a pain in the butt and wallet to have to buy a new swimsuit each summer (unless you want a new look and have disposable income), but if you’re strapped for cash then it’s better to know how to maintain your original one so it can last for years.

As mentioned, time, or more accurately, frequency of use, will wear down your swimsuit much faster even if you’re maintaining it properly. If you are going to the pool or beach everyday, expect to have to replace your swimsuit faster than someone who only goes on the weekends. There’s really no getting around this except to wear it less often which is not a solution.

Even more importantly, how well you take care of your swimsuit outside of the water is vital in ensuring its longevity. Chlorinated water is full of chlorine and other chemicals, and they can wear down the elastic materials in your swimsuit. The same is true of saltwater. Over time, this will cause the swimsuit to get bigger (stretch out), and as we established, going to the pool less is out of the question.

So what do you do? Immediately after swimming, thoroughly rinse your swimsuit. Get as much of the chlorine and other chemicals off the swimsuit ASAP. You don’t have to use soapy water every time, but aim to wash your swimsuit with detergent at least once a week to really clean the chemicals off.

Another note: always wash your swimsuit by hand and with cold water. Do not use the washing machine even with a cold wash cycle, do not use hot water even if you’re washing by hand, and absolutely do not use the dryer either. Everything needs to be done the old-school way: by hand, and then hung somewhere to dry.

Even drying your swimsuit requires the utmost care. Do not hang it up anywhere in direct sunlight; the sun’s UV rays can wear down the materials. Make sure the location you’re hanging the swimsuit in is well-ventilated, otherwise it can get quite musty and take longer to dry.

Furthermore, even when you’re squeezing the water out of the swimsuit after washing it, do not twist or wring too hard, as this can stretch the material out. Instead, sandwich your swimsuit between two towels and either squeeze the water out with the palms of your hands pressed together, or step on the swimsuit while it’s covered in towels to get the water out in a way that does not twist the swimsuit.

How to pick the right swimsuit size in the first place

If you’re worried about a swimsuit stretching out or shrinking too much, it might be because your swimsuit doesn’t fit you very well in the first place.

Sorry to sound like a broken record, but swimsuits naturally stretch out over time. That means that you should be aiming to get a swimsuit that is either true to size or a size down. This can help you account for the inevitable stretching that your swimsuit will experience.

Buying a size up may be okay if you never plan on going in the water, preferring instead to lounge poolside or by the beach to soak up the sun. Any swimsuit that you actually plan to wear in the water should probably be on the smaller side.

If you want more in-depth advice on how you can accurately find a swimsuit that fits you, then read our article on exactly that topic.

So, to recap: swimsuits get bigger in the water whether you want them to or not. They can also shrink if you expose them to heat. Saltwater and the chemicals in pool water can wear down your swimsuit material, causing them to stretch much faster than normal. Make sure to thoroughly rinse and properly dry your swimsuit after each use to ensure they can have a long lifespan. Otherwise, be prepared to buy a new swimsuit every few months.