How to Get Period Blood Out of Swimsuit Bottoms

JANE FLANAGAN / PERIODS

Leaks happen. For those with heavy periods, they can be a monthly reality. For others, they’re a nighttime occurrence. Nobody relishes these moments, but perhaps one of the more excruciating scenarios is to leak when you’re in swimwear.

We’re going to offer some tips for avoiding period stains altogether, as well as some tricks for getting rid of period stains if they’ve already occurred.

The Simple Solution for Period Stains: Switch to Period Swimwear!

Period swimwear is an all-in-one product that will absorb menstrual blood and protect you from leaks. It also happens to be a super stylish swimwear option for you to wear poolside, beachside, or even just lounging in your backyard. 

How Does Knix Period Swimwear Work?

Period swimwear (also known as leakproof swimwear or period-proof swimwear) is a relatively new offering. Basically, it leverages the same technology as period underwear with some added secret protection to make it work in water.

The best part? Just like period underwear, period swimwear looks just like regular swimwear and comes in a variety of styles and fits, from bikini bottoms to one-pieces. You’ll even have a choice of color!

So how exactly does Knix period swimwear work? The layers in the gusset of the swimsuit work to trap and absorb your period, so it doesn't leak in the water (or on land!) Our Swimwear features the same Leakproof Technology as our Period Underwear with an additional thin layer of waterproof material for extra protection.

The inner layers absorb the blood and trap it, so there's no leakage when you swim and no dreaded period stains. When it goes in the laundry with detergent, it releases through the top layer— leaving your swimwear fresh and clean for tomorrow's laps.

Knix Leakproof Swimwear has a super discreet absorbent pad in the gusset liner.

How to Remove Blood Stains from a Regular Swimsuit

Act Swiftly on the Blood Stain - If You Can

The fresher the blood stain, the easier it will be to ensure you get all the period blood out of your underwear. Same idea for most stain treatments: the sooner the better. We know it’s not always possible to act immediately on fresh blood stains, but if you can - do it.   

You’ll probably be amazed how much of the stain comes out of your swimsuit if you get to it when it’s fresh/still damp.

Ignore the Hot Water Tap: Go for Cold Water

The biggest mistake people make when trying to get period blood out of swimwear is to run the hottest water possible over it. 

It’s a natural instinct. We wash dishes in hot water for a good reason, right? But hot water can have the opposite effect on fabric and cause blood stains to set in, making them even more difficult to remove.

Instead, go for ICE COLD water. Run cold water over the stain for a few minutes, letting the running cold water do the work. Odds are, you’ll see a lot of the period blood wash away from your bathing suit right away! Feels counter intuitive, we know - but it’s highly effective. 

Kill the Blood Stain With Kindness

If the period stain is a little more stubborn, you might be tempted to put some muscle into it. But remember: Swimwear is made of light, thin fabrics. They are resilient, but that doesn’t mean you want to tug and stretch them by scrubbing roughly.

Instead, try gently using an old, soft toothbrush to delicately scrub the area where any blood has set on your swimsuit. If you use liquid laundry detergent to remove period stains, choose soap designed for delicate fabrics.

Stain Remover Products Can Help

If you need to up the ante, reach for your household stain removal products. Read the product instructions to make sure they can be used on the fabric of your swimsuit (usually a nylon or polyester blend.) And remember: Products with bleach are generally not to be used on darker fabrics.

Again, work the product in gently. That old toothbrush can be a handy tool here as it allows you to pinpoint the exact area where there’s period blood on the gusset of your swimsuit. And follow the instructions closely: If you need to let the product sit before rinsing, do.

Or, Try These Household Products

No stain removal products handy while away on holiday? Don’t worry. You can even figure out how to get blood stains out of swimwear, underwear, and clothing with some basic household products!

1. Hydrogen Peroxide

Hydrogen peroxide is a common antiseptic, so you might find you have some in your medicine cabinet. What you may not know is that hydrogen peroxide can also be very effective for stain removal. Note: Hydrogen peroxide is a bleaching agent, so it should only be used on light-colored bathing suits. Avoid using hydrogen peroxide on any dark color fabrics.

Pour some hydrogen peroxide into a small bowl and either dip the stained fabric area into the liquid, or use your trusty old toothbrush to work the liquid into the stain.

2. Lemon Juice

The acid in lemon can actually help break down stains on your swimsuit. If you've got a lemon lying around, cut it in half. Then rub the lemon over the bloodstain. Continue until you see the stain has disappeared. You may have to repeat this process a few times for the stain to disappear fully. Finish by washing your undies in cool or cold water.

3. Salt

Salt is another great household stain-buster. You can quite literally use the same salt you sprinkle on your dinner! Just mix one part salt and two parts cold water. Gently apply the salt mix to the stain and watch it disappear. Be sure to rinse the fabric well when you're done.

4. Baking Soda

Similar to salt, you can also make a paste from cold water and baking soda (yes, the kind you put in your fridge or freezer to deodorize it). Mix water and baking soda to form a paste and apply to the stained area. Again, always rinse well once you're done. Repeat if you don't get it all out the first time!

Wanna Get Even Weirder?

This might be getting a little peculiar, we admit…but there are even wackier ways to get those stains out of your undies. Feel like experimenting? Try these: 

5. Aspirin

Follow the same method as with the salt or baking soda: Just crush a few aspirins and mix with water to form a paste. Apply the mixture to the stain, and you should see it start to budge.

6. Unseasoned Meat Tenderizer

Okay, this one is truly out there. Meat tenderizer is a blend of salt and bromelain used to tenderize... you guessed it... meat. That combo of ingredients also makes it a great stain remover. Use the same method as before: Form a paste out of the tenderizer mixed with water. Then watch the meat tenderizer do its job. Rinse with plenty of cold water.

If you've got dried blood stains, the same tips apply, but you may want to soak dried period blood stains overnight. All stains are more stubborn once dried (which is why it's easier to address fresh stains), but the right stain remover and a lot of patience can have an effect on even majorly stubborn stains.

Other Common Sense Advice for Handling Your Period by the Pool

Keep a Cover-Up Handy

A cover-up is an ideal piece of clothing to have handy when you’re in your swimsuit. Maybe you want to sidle up to a cabana for a drink, hit a beach-side patio for lunch, or simply protect your modesty (and your skin) when you’re not in the water. A cover-up lets you do just that.

Cover-ups are items of clothing that are marketed alongside swimwear to be worn on the beach or poolside. Some of them can even be elegant enough to transition to dinner or drinks. They’re ideal items of clothing if you’re spending time at a resort, on a cruise, or just enjoying a hot day by the pool.

Cover-ups are usually sheer garments made of lightweight fabric. This means they are great for packing and will fit easily in your luggage, beach bag, or even fold into your purse. Despite their easy-to-stow nature, they still manage to offer enough coverage in case of an emergency leak. You can always just throw one on until you get to a washroom. 

Wear Period Protection

Your period does not stop when you’re in the water. That applies to any water (bathwater, ocean, or pool.)

What can happen is that the water pressure can lighten your flow, which may create the illusion that you’re not bleeding. However, if you cough, sneeze, laugh or exert yourself otherwise, the pressure of your period blood can break through the surrounding water.

Obviously, the water will quickly dilute your blood, so it’s unlikely you’ll see a streak in the water. But basically, it’s not worth rolling the dice on swimming without some form of protection, especially in a pool where other swimmers may be sharing the water in relatively close proximity.

Note: Pads and panty-liners are NOT good options for swimming, as they will simply absorb water to their maximum absorption and become sodden, heavy, and messy.

So you need some form of protection… The go-to protection for swimming is traditionally a tampon. Many of us are comfortable wearing tampons as our regular period protection, so we have confidence in them to absorb our flow. We know how often we need to change them, and it’s almost a no-brainer to trust them in the water.

A menstrual cup is another alternative: Made of silicone or latex rubber and is designed to catch and collect your blood (rather than absorb menstrual blood like a tampon.) The cup is folded and inserted into the vagina (similar to inserting a diaphragm.) It then opens to form a seal against the wall of your vagina that prevents leaks. The blood then collects in the cup.

Different brands of cups come in different shapes, so it can be worth trying a few to find the one that’s most comfortable for you. Like a tampon, you shouldn’t feel a menstrual cup once it’s inserted.

Menstrual cups are typically reusable. You remove them by pinching the base and pulling, which will release the seal. Then you empty the cup into the toilet, wash it (and your hands) carefully with soap and water, and reinsert it once it’s fully rinsed. At the end of your menstrual cycle, once your period has ended, it’s advisable to sterilize your cup in boiling water.

Change Your Tampon or Menstrual Cup Frequently

Nobody knows your cycle better than you do. You know your heavy days and your light days, whether you’re prone to blood clots, etc. So don’t forget about your cycle when you’re enjoying a beach day. Changing your tampon or menstrual cup at the recommended frequency is the biggest way to avoid leaks.  

Pushing the limits of absorption is especially not recommended for tampons. They can absorb water, too, so they may become saturated more quickly when you’re swimming. Remember, you may not “feel” a leak the way you usually do when you’re in and out of water. So stay vigilant!

Double-Up Protection With Period Swimwear

Pairing your tampon or menstrual cup with period swimwear can give you extra confidence on your heaviest flow day, or even just while you’re getting used to relying on period swimwear. If you already use tampons or menstrual cups, this is a great way to ease into feeling confident with period swimwear.

Keep in mind you absolutely do not need to depend on additional products while swimming. If you want to rely fully on your period swimwear, that’s exactly what it’s designed for. How handy that it can absorb three tampons worth of menstrual blood all on its own! You could always start by first wearing it on your light period days to build up your confidence. 

Written by Jane Flanagan — Updated on March 5, 2023

We hope you found this post informative — but remember: we’re not doctors and this post is not medical advice! While all posts are fact-checked and well researched, we always recommend you chat with your doctor about any questions or concerns you might have regarding a medical condition. We’re here to support and educate, but never with the aim of disregarding professional medical advice you’ve been given. Phew, now that that’s out of the way, you can go on living unapologetically free.