Period Swim Full-Coverage Bikini Bottom

More comfortable with more coverage? We made these just for you. A mid-rise fit with fuller bum coverage than our regular bikini bottoms, and the leak-fighting power of about the same as 2-3 super tampons! Perfect for beach days, pool parties and all the hangouts you would’ve missed.

Layer 1: A silky-smooth top layer that sits comfortably against the skin.

Layer 2: A highly-absorbent middle layer designed with our leakproof technology to absorb about the same as 2-3 super tampons.

Layer 3: A waterproof outer layer never swells.

Other Features:

- Bum coverage: Full

- Fully lined

- Super-discreet liner

- 50+ UPF protection

Feel full of confidence in full-coverage swimwear.
Image of a absorbancy surrounding text
Absorbs about the same as 2-3 super tampons of period blood.
Image of a moisture fabric surrounding text
Rapidly absorbs moisture to keep you fresh and dry.
Image of a light and comfy surrounding text
Thin, subtle, and designed to feel just like regular swimwear.
Image of a machine washable surrounding text
Simply machine wash cold and lay flat to dry.

More comfortable with more coverage? We made these just for you. A mid-rise fit with fuller bum coverage than our regular bikini bottoms, and the leak-fighting power of about the same as 2-3 super tampons! Perfect for beach days, pool parties and all the hangouts you would’ve missed.

Layer 1: A silky-smooth top layer that sits comfortably against the skin.

Layer 2: A highly-absorbent middle layer designed with our leakproof technology to absorb about the same as 2-3 super tampons.

Layer 3: A waterproof outer layer never swells.

Other Features:

- Bum coverage: Full

- Fully lined

- Super-discreet liner

- 50+ UPF protection

Body: 85% Nylon, 15% Spandex

Lining: 85% Nylon, 15% Spandex

Gusset: Fresh Fix Technology®, Polyurethane Film


Machine wash cold and lay flat to dry. Do not bleach, iron, or dry clean. 


Additional Product Ingredient Information

For items with a 20% or more discount, you may exchange for another item or return for store credit. No refunds can be accommodated. 

Items marked as “Flash Sale” or “Clearance” are final sale, meaning no returns, exchanges or refunds can be accommodated. No exceptions. 

Please note: 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.

 FOR THE PLANET
FOR REAL LIFE
FOR THIS GENERATION
FOR THE PLANET
FOR REAL LIFE
FOR THIS GENERATION
FOR THE PLANET
FOR REAL LIFE
FOR THIS GENERATION
FOR THE PLANET
FOR REAL LIFE
FOR THIS GENERATION
FOR THE PLANET
FOR REAL LIFE
FOR THIS GENERATION
FOR THE PLANET
FOR REAL LIFE
FOR THIS GENERATION
FOR THE PLANET
FOR REAL LIFE
FOR THIS GENERATION
FOR THE PLANET
FOR REAL LIFE
FOR THIS GENERATION
FOR THE PLANET
FOR REAL LIFE
FOR THIS GENERATION
FOR THE PLANET
FOR REAL LIFE
FOR THIS GENERATION
FOR THE PLANET
FOR REAL LIFE
nothing is TMI here—we promise.

Our period swim bottoms contain a triple-layer gusset that absorbs your flow and locks in leaks, whether you're in or out of the water. When they go in the wash with detergent, the blood releases through the top layer—leaving your swimwear fresh and clean for next time. Yes, your other clothes will remain stain-free!

Here's the breakdown of our 3-layer leakproof technology:

Layer 1: A silky-smooth top layer that sits comfortably against the skin.

Layer 2: A highly-absorbent middle layer designed with our leakproof technology to absorb up to 1-3 tampons worth of period blood.

Layer 3: A waterproof outer layer prevents swelling. 

Not always. When your flow is light, our swimwear can be worn alone without any additional period protection. On super heavy days, we recommend wearing a tampon or menstrual cup with your swimwear. Every period is different though, and we recommend doing whatever makes you feel most confident.

Machine wash cold and lay flat to dry. Do not bleach, iron, or dry clean.

Check out our size chart here. 

Yes! All of our regular price swim bottoms and one-pieces are eligible for a return or exchange within 30 days of delivery, as long as the original sanitary strip and tags are attached. Our swim tops are eligible for a return or exchange within 30 days of delivery with original tags attached.

Absolutely! The leakproof liner built into all of our period swimwear is undetectable, so they look and feel just like regular swimwear.

Our styles are made to fit teen bodies. For period swimwear in adult sizes, please visit Knix.

 COMFORTABLE
JUST PLAIN BETTER
REUSABLE
COMFORTABLE
JUST PLAIN BETTER
REUSABLE
COMFORTABLE
JUST PLAIN BETTER
REUSABLE
COMFORTABLE
JUST PLAIN BETTER
REUSABLE
COMFORTABLE
JUST PLAIN BETTER
REUSABLE
COMFORTABLE
JUST PLAIN BETTER
REUSABLE
COMFORTABLE
JUST PLAIN BETTER
REUSABLE
COMFORTABLE
JUST PLAIN BETTER
REUSABLE
COMFORTABLE
JUST PLAIN BETTER
REUSABLE
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JUST PLAIN BETTER
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COMFORTABLE
JUST PLAIN BETTER
Reviews
average rating 4.5 out of 5
Based on 71 reviews
  • 5 Stars
    53 Reviews
  • 4 Stars
    9 Reviews
  • 3 Stars
    1 Review
  • 2 Stars
    4 Reviews
  • 1 Star
    4 Reviews
87% of reviewers would recommend this product to a friend
Quality
Rated 4 out of 5
Comfort
Rated 4 out of 5
Effectiveness
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
Write a Review
Review posted
Reviewed by Renee D.
Verified Buyer
Period Swim Full-Coverage Bikini Bottom
Reviewing
Period Swim Full-Coverage Bikini Bottom
Rated 5 out of 5

Excellent period brief

I bought these for my nearly 13 year old daughter. Purchased size medium and they fit perfectly. She is a women's size small or 4. She is a competitive swimmer and she wears the brief under her full race suit. This style has good coverage in the back and didn't bunch or ride. A great option for young swimmers!

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I recommend this product
Comfort
Rated 5 out of 5
Fit
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
Effectiveness
Rated 5 out of 5
Ease of Use
Rated 5 out of 5
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Reviewed by Alexandra A.
Verified Buyer
Period Swim Full-Coverage Bikini Bottom
Reviewing
Period Swim Full-Coverage Bikini Bottom
Rated 5 out of 5

Perfect

Haven’t tried yet, but they fit! I am excited for my daughter to try these this summer

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I recommend this product
Comfort
Rated 5 out of 5
Fit
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
Effectiveness
Rated 3 out of 5
Ease of Use
Rated 5 out of 5
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Review posted
Reviewed by K
Verified Buyer
Period Swim Full-Coverage Bikini Bottom
Reviewing
Period Swim Full-Coverage Bikini Bottom
Band Size
N/A
Pant Size
Teen 12-16
Size Purchased
S
Rated 5 out of 5

Swim bottoms

Great quality!

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I recommend this product
Quality
Rated 5 out of 5
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 Fits Small, 0 is True to Size and 2 is Fits Large
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Review posted
Reviewed by Jamie K.
Verified Buyer
Period Swim Full-Coverage Bikini Bottom
Reviewing
Period Swim Full-Coverage Bikini Bottom
Band Size
32"
Pant Size
Teen 00-2
Size Purchased
S
Usage
  • Pool
Rated 5 out of 5

Excellent fit

Excellent fit and coverage

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I recommend this product
Quality
Rated 5 out of 5
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 Fits Small, 0 is True to Size and 2 is Fits Large
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Review posted
Reviewed by LF
Verified Buyer
Period Swim Full-Coverage Bikini Bottom
Reviewing
Period Swim Full-Coverage Bikini Bottom
Rated 5 out of 5

Full Coverage Bikini Bottoms

My daughter is super excited to try these - she now can take part in summer fun and not miss out on swim birthday parties. She's normally a small but we also purchased a Medium to have an extra one on hand. We will purchasing more most definitely.

Very fast shipping!

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I recommend this product
Comfort
Rated 4 out of 5
Fit
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
Effectiveness
Rated 4 out of 5
Ease of Use
Rated 5 out of 5
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