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Travel Bag
$15.00 USD

Holds up to 7 pairs of undies

Color: Black Limited Edition

Size:

Size:

Mix, Match & Save

Period Swim Full-Coverage Bikini Bottom

$45.00 USD

Buy 3+ SAVE 15%
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Absorb about 2 super tampons

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Lower to mid-rise fit

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Full coverage style

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Premium UPF 50+ fabric

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Machine washable

| Set Sail
| Set Sail
| Set Sail
| Set Sail

Color: Set Sail Limited Edition

Size:

True to Size

Size:

Size and Fit Guide

FREE Shipping on orders $70+

Shipping

Shipping

Processing Timelines

Please allow 1-2 business days for our warehouse team to pack and ship your order. During peak periods such as sales, holidays and product launches, please allow up to 4 business days for us to process your order. Once an order is placed, we cannot guarantee any address updates, order changes or cancellations. Orders placed on Friday after 1PM will not be shipped until the following Monday.

Delivery Timelines

For the most up to date delivery time estimates, please refer to the shipping timeline at checkout. All transit times are measured in business days which are Monday-Friday, excluding holidays.

Please note, all shipping timelines are estimates and are not guaranteed.

US Orders

Orders within the United States will be shipped with DHL and USPS or FedEx based on your address and carrier availability.

Please note: Orders over $700 may be subject to customs/duties upon receipt. Customers are responsible for any customs/ duties upon receipt of order. Orders are shipped from Canada.

Standard US shipping is free on eligible orders over $70 USD*. Orders under $70 USD are $10 USD for standard shipping depending on location.

*After discounts, before shipping and taxesWe are not able to ship to US territories (including Puerto Rico, U.S. Virgin Islands, Guam, Northern Mariana Islands and American Samoa) at this time.

Return Policy

Return Policy

Return Policy

Return policy varies by product, please check if your item is refund or exchange eligible by viewing our full policy here.

5 stars is really not enough “Seeing my 11 year old never skip a beat is invaluable! She never had to think twice about being on her period while we were at the beach, and most importantly to her, no one else had to know.”

- Kellie H.

Swim Style

A full coverage style with a mid-rise fit and full bum coverage.

Worry-Free Protection

Discreet, built-in protection that absorbs about 2 super tampons worth.

Sun-Smart Protection

UPF 50+ fabric protects your skin while you soak up the sun.

Zoom

| Set Sail
| Set Sail
| Set Sail
| Set Sail

How to Choose?

Heavy

Drop
Drop
Drop
Drop
Drop
  • Perfect for overnight protection or your teens heaviest days when changing into a fresh pair might not be convenient.
  • tsp
    about 8-14 tsp
  • pad
    about 1.5-3 regular pads
  • tampon
    about 4-7 super tampons
  • cup
    about 1.5-3 menstrual cups

Light

Drop
Drop
Drop
Drop
Drop
  • Ideal for lightest period days, spotting, sweat and discharge.
  • tsp
    about 1-3 tsp
  • pad
    about 1-3 pantyliners
  • tampon
    about 1-3 regular tampons
  • cup
    about 0.5 menstrual cups

Moderate

Drop
Drop
Drop
Drop
Drop
  • Ideal for medium period days, discharge and sweat.
  • tsp
    about 4-8 tsp
  • pad
    about 1-1.5 regular pads
  • tampon
    about 2-4 super tampons
  • cup
    about 0.5-3 menstrual cups

Ultra

Drop
Drop
Drop
Drop
Drop
  • Ultimate peace of mind. For the heaviest period days or overnight protection.
  • tsp
    about 15-20 tsp
  • pad
    about 1.5-2.5 super pads
  • tampon
    about 7-11 super tampons
  • cup
    about 2-3 menstrual cups
LEAKPROOF SWIM WORKS IN LAYERS

Built-in protection that feels like nothing at all.

Looks just like regular swimwear. Non-swelling liner and patented no-show design.

Soft Top Layer

Top Layer

Smooth and comfortable liner in swimsuit fabric.

Your questions, answered.

4.5
Rated 4.5 out of 5 stars
Based on 86 reviews
86 reviews
  • Rated 5 out of 5 stars
    3 weeks ago
    Wow

    Amazing product. Really hugs the hips.

    Ben
  • Rated 5 out of 5 stars
    1 month ago
    My daughter loves it

    It’s wonderful

    Rufina A.
    Verified Buyer
  • Rated 5 out of 5 stars
    5 months ago
    Period swim full coverage bikini bottom

    The full coverage fit is age appropriate and wish you also sold non-period bottoms of same full coverage profile and in fun colors. It is hard to find a good full coverage bottom in most of the bathing suit stores - they are all so cheeky and/or high cut.

    Beth S.
    Verified Buyer
  • Rated 1 out of 5 stars
    7 months ago
    Product never arrived 19 days and counting

    Product never has arrived. It’s been stuck with USPS since August 5th and the postal service can’t figure out where it’s at and the Knox customer service rep didn’t offer any help or advice either. So here I sit for 19 days now being charged for something I never received. No refund no offer to send again nothing. Totally disappointed by this purchase process and the lack of support along the way.

    Julie S.
    Verified Buyer
  • Rated 5 out of 5 stars
    7 months ago
    Great swim bottom

    Looks great and works vey well. It's generic enough to mix & match with different tops. I got a couple of them so she can just change them without changing the top.

    Parastoo G.
    Verified Buyer
  • Rated 5 out of 5 stars
    7 months ago
    Looks cute, works great

    These swim bottoms were a life saver on our vacation! They work extremely well and they are super cute.

    Susan K.
    Verified Buyer