Leakproof Cotton Modal Underwear Bikini

A highly absorbent bikini in super soft cotton modal fabric, with our patented leakproof technology that absorbs the same as about 2 super tampons or 1 regular pad built right in.

it doesn’t get any softer than this.
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Holds about 2 super tampons' or 1 regular pads' worth of blood.
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Allows air to circulate to keep you cool and dry.
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Texture feels smooth against the skin for added comfort.

A highly absorbent bikini in super soft cotton modal fabric, with our patented leakproof technology that absorbs the same as about 2 super tampons or 1 regular pad built right in.

Machine wash cold with mild detergent, do not bleach, tumble dry on low.


Body: 47% Cotton, 47% Modal, 6% Spandex

Lining: 84% Modal, 8% Seaweed, 8% Spandex 

Gusset: Leakproof Technology®, 100% Polyester, PU Film 


Additional Product Ingredient Information

Items marked as "Sale", "Clearance" or “Black Friday Deal" are final sale, meaning no returns, exchanges or refunds can be accommodated. All final sale items are not eligible for our First Pair Risk-Free Policy.

We offer free standard shipping on all orders over $70. We ship our items via DHL or Canada Post depending on your location. Please allow 1-2 business days for your items to be processed and shipped. During high volume periods, your order may take up to 7 business days to dispatch from our warehouse location.


US Orders: Please allow 3–10 business days for orders to arrive. 

International Orders: Please allow 10–25 business days for orders to arrive.  


NOTE: Orders placed on Friday after 1 PM will not be processed until the following Monday.   

CANADIAN CUSTOMERS: Shop www.knixteen.ca to order in Canadian currency.

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FOR THIS GENERATION
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for the planet!
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FOR THIS GENERATION
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for the planet!
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FOR THIS GENERATION
Image of a chrome heart surrounding text
for the planet!
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FOR THIS GENERATION
Image of a chrome heart surrounding text
for the planet!
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FOR THIS GENERATION
Image of a chrome heart surrounding text
for the planet!
Image of a chrome heart surrounding text
FOR THIS GENERATION
Image of a chrome heart surrounding text
for the planet!
Image of a chrome heart surrounding text
FOR THIS GENERATION
Image of a chrome heart surrounding text
for the planet!
Image of a chrome heart surrounding text
FOR THIS GENERATION
Image of a chrome heart surrounding text
for the planet!
Image of a chrome heart surrounding text
FOR THIS GENERATION
Image of a chrome heart surrounding text
for the planet!
Image of a chrome heart surrounding text
FOR THIS GENERATION
Image of a chrome heart surrounding text
for the planet!
Image of a chrome heart surrounding text
FOR THIS GENERATION
Image of a chrome heart surrounding text
for the planet!
Image of a chrome heart surrounding text
FOR THIS GENERATION
Image of a chrome heart surrounding text
for the planet!
Image of a chrome heart surrounding text
FOR THIS GENERATION
Image of a chrome heart surrounding text
for the planet!
Image of a chrome heart surrounding text
FOR THIS GENERATION
Image of a chrome heart surrounding text
for the planet!
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FOR THIS GENERATION
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for the planet!
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FOR THIS GENERATION
nothing is tmi here—we promise.
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Each pair has a built-in liner that absorbs period blood. Kt Period Underwear is categorized by lightest, medium and heavy flows so you can find the right pair for your teen’s needs.

All of our period underwear, swimwear, reusable pads, and activewear have our patented leakproof technology built right in. Liner’s are discreet and comfortable, and fit for your teen’s unique flow. 

That’s up to your teen or tween! Every flow and comfort level is different.

Depending on the absorbency level of the period underwear and the heaviness of your teen’s flow, they can wear our period undies on their own or as a backup to tampons or menstrual cups. 

We always recommend they choose an option that makes them feel most confident!

Step 1: Give your teens underwear a quick rinse under cold water.
Step 2: Throw it in the washing machine with your regular clothes. Wash on cold with mild detergent (no softener or bleach).
Step 3: There are two ways to dry them depending on the undies you have: lay flat to dry for medium absorbency products, or tumble dry on low for high to super absorbency products.
Step 4: That’s it! No ironing needed.

Check out our size chart here. If you want some help, we have virtual fitters ready on deck to help your teen find their perfect fit. Book a video call with them today.

Because they’re, well, underwear, we can’t accept exchanges or returns on used items. BUT your teen can try their first pair on your first order risk-free for 30 days!


If you ordered the wrong size of period underwear, we’ll send you a different pair at no cost or offer you a standard refund within 30 days of delivery (excluding original shipping fees).


If your order included multiple period underwear, open, wash, and wear one pair only. That way if you don’t love them, any unopened packages from the same purchase will be eligible for an exchange or standard refund (excluding original shipping fees).


All unopened packages will be donated to local organizations to support people in need.


Underwear purchased as part of the Period Party Sale is eligible for exchange or store credit only. No refunds. Sale items are not eligible for our First Pair Risk Free Policy.


Super Sleepover Shorts and Reusable Pads purchased as part of the Period Party Sale are final sale. No exchanges or refunds can be accommodated.

Super Absorbency

Absorbs 9–12 tsp (45–60 ml) of blood—that’s about 9–12 regular tampons or pads! Perfect for overnight protection or your teens heaviest days when changing into a fresh pair might not be convenient.


High Absorbency

Absorbs 4–8 tsp (20–40 ml) of blood, or the equivalent of 4–8 tampons or pads. These are perfect for heavy flow days.


Medium Absorbency

Absorbs up to 3 tsp (15 ml), or about 3 tampons or pads worth of blood. Ideal for light to medium flow days or as backup to tampons or period cups.

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Sustainable
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Absorbent
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Comfortable
Image of a chrome heart surrounding text
Sustainable
Image of a chrome heart surrounding text
Absorbent
Image of a chrome heart surrounding text
Comfortable
Image of a chrome heart surrounding text
Sustainable
Image of a chrome heart surrounding text
Absorbent
Image of a chrome heart surrounding text
Comfortable
Image of a chrome heart surrounding text
Sustainable
Image of a chrome heart surrounding text
Absorbent
Image of a chrome heart surrounding text
Comfortable
Image of a chrome heart surrounding text
Sustainable
Image of a chrome heart surrounding text
Absorbent
Image of a chrome heart surrounding text
Comfortable
Image of a chrome heart surrounding text
Sustainable
Image of a chrome heart surrounding text
Absorbent
Image of a chrome heart surrounding text
Comfortable
Image of a chrome heart surrounding text
Sustainable
Image of a chrome heart surrounding text
Absorbent
Image of a chrome heart surrounding text
Comfortable
Image of a chrome heart surrounding text
Sustainable
Image of a chrome heart surrounding text
Absorbent
Image of a chrome heart surrounding text
Comfortable
Image of a chrome heart surrounding text
Sustainable
Image of a chrome heart surrounding text
Absorbent
Image of a chrome heart surrounding text
Comfortable
Image of a chrome heart surrounding text
Sustainable
Image of a chrome heart surrounding text
Absorbent
Image of a chrome heart surrounding text
Comfortable
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Sustainable
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Absorbent
Reviews
average rating 4.6 out of 5
Based on 690 reviews
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94% of reviewers would recommend this product to a friend
Quality
Rated 4 out of 5
Comfort
Rated 4 out of 5
Sizing
Rated 0 on a scale of minus 2 to 2, where minus 2 is Fits Small, 0 is True to Size and 2 is Fits Large
Effectiveness
Rated 4 out of 5
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Reviewed by Daniela L.
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Leakproof Cotton Modal Underwear Bikini
Reviewing
Leakproof Cotton Modal Underwear Bikini
I'm a...
Parental Figure
I purchased for...
A Teenager/Tween
Pant Size
Kids 16-20
Size Purchased
S
Usage
  • Back-up Protection
Rated 5 out of 5

Great fit

Nice product would buy again

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Quality
Rated 5 out of 5
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Rated 5 out of 5
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Rated 0 on a scale of minus 2 to 2, where minus 2 is Fits Small, 0 is True to Size and 2 is Fits Large
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Rated 4 out of 5
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Reviewed by Emma L.
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Leakproof Cotton Modal Underwear Bikini
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Leakproof Cotton Modal Underwear Bikini
I'm a...
Parental Figure
I purchased for...
A Teenager/Tween
Pant Size
Teen 12-16
Size Purchased
XL
Rated 5 out of 5

Love these!

Great and easy to care for.

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Quality
Rated 5 out of 5
Comfort
Rated 5 out of 5
Sizing
Rated 0 on a scale of minus 2 to 2, where minus 2 is Fits Small, 0 is True to Size and 2 is Fits Large
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Rated 4 out of 5
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Reviewed by Crystal B.
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Leakproof Cotton Modal Underwear Bikini
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Leakproof Cotton Modal Underwear Bikini
Rated 5 out of 5

IT'S OFFICIAL... The Cotton Bikinis are MY FIT =D

The Cotton Bikinis NEVER FAIL for me. My body is a little thicker on the thighs and around the belly button areas and require a little extra coverage in the pelvic area (definitely not flat or narrow in that area lol), and these fit PERFECTLY!! They come just high enough to hold my tummy and NOT fold down, and plenty of leg room WITHOUT feeling too narrow in crotch area... finally giving me FULL COVERAGE =))

I tend to fluctuate between a size 6 and 7 in standard US underwear sizes, and these in Large fit me best.

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Reviewed by Deborah W.
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Leakproof Cotton Modal Underwear Bikini
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Leakproof Cotton Modal Underwear Bikini
Rated 5 out of 5

Comfort

I like the style and fit

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I recommend this product
Comfort
Rated 5 out of 5
Effectiveness
Rated 5 out of 5
Sizing
Rated 0 on a scale of minus 2 to 2, where minus 2 is Runs Small, 0 is True to Size and 2 is Runs Large
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Review posted
Reviewed by Donna J R.
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Leakproof Cotton Modal Underwear Bikini
Reviewing
Leakproof Cotton Modal Underwear Bikini
I'm a...
Parental Figure
I purchased for...
A Teenager/Tween
Pant Size
Kids 8-10
Size Purchased
XS
Usage
  • Primary Protection
  • Incontinence
  • Period
  • Back-up Protection
  • Sweat
Rated 5 out of 5

Great!

My daughter finds these very comfortable and wears them as everyday underwear. They wash and dry well without shrinkage. Very well made.

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I recommend this product
Quality
Rated 5 out of 5
Comfort
Rated 5 out of 5
Sizing
Rated 0 on a scale of minus 2 to 2, where minus 2 is Fits Small, 0 is True to Size and 2 is Fits Large
Effectiveness
Rated 5 out of 5
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