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Leakproof UltraThin™ No-Show Bikini 3-Pack*

$68.00 USD

Absorbs about 2.5 super tampons

Invisible under clothes

Moderate protection without the bulk

Machine washable

Front view of model highlighting the coverage and fit
Front view of model highlighting the coverage and fit

Color: Eucalyptus/Rose Quartz/Rosewood Limited Edition

Size:

True to Size

•

Size:

Size and Fit Guide

Free Shipping on orders $100+

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.


Split Shipments

Most orders will ship from a single warehouse. However, we occasionally ship from a combination of warehouse locations, so you may receive your order in multiple parts. If items from your order ship in separate packages, we’ll send you tracking information for each package when it becomes available.

Delivery Timelines

For the most up-to-date delivery time estimates, please refer to the shipping timeline at checkout. Delivery timelines do not include processing times. See above for details. 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.

We 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.

Easy Exchanges within 30 Days

Returns

Returns

Sale & Last Call

Items discounted 30% and below are eligible for size exchange or store credit. Items discounted above 30% and above are final sale – no refunds, store credits, or exchanges can be accommodated.

Free Returns

Knix covers the return shipping fees for exchanges and refunds initiated through our Return & Exchange Portal. Exchange orders initiated through our Return & Exchange portal are also eligible for free shipping within the USA and Canada. Please note, the shipping fees on your original order are non-refundable.

Return Policy

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

Rewards Members Earn 68 Points

"These are my favorite of all the period underwear styles I have tried, and I now own enough for a full cycle of wear."

- InStyle

Comfort-First Fit

Bikini silhouette with a classic mid-rise fit, medium hip and bum coverage.

Worry-Free Protection

Our newest leakproof innovation provides more absorbency without the bulk. Patented 360 LeakSeal™ technology locks in leaks at every edge.

Moderate Absorbency

Absorbs 2.5 super tampons worth of liquid—perfect for moderate flow days, light bladder leaks, and sweat. The carbon cotton gusset top layer keeps you dry.

No-Show Style

Buttery-soft and smooth fabric gives a seamless look and feel. Disappears under clothes, even leggings.

Easy to Wash

Machine washable, just like your regular underwear.

Zoom

How to Choose?

Essential

  • • Days you don’t need leak protection. Everyday freshness and moisture wicking.
  • tsp
    0 tsp

Heavy

  • • Extra peace of mind. For the first days of your cycle, light bladder leaks, or a full night's sleep without a leak.
  • 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

  • • Daily freshness. For sweat, discharge, period spotting, or backup protection.
  • tsp
    about 1-3 tsp
  • pad
    about 1-3 pantyliners
  • tampon
    about 1-3 regular tampons
  • cup
    about 0.5 menstrual cups

Moderate

  • • For mid-cycle flow, surprise cough or sneeze leaks, or a really sweaty spin class.
  • 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

  • • Ultimate peace of mind. For the heaviest period days, light bladder leaks, unexpected postpartum flow, 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
4.4
Rated 4.4 out of 5 stars
Based on 808 reviews
What our customers are saying
Customers say these period underwear are comfortable and provide excellent protection without the bulkiness of traditional pads. Many appreciate the thin, no-show design that works well under clothing and the stylish patterns like polka dots. Users frequently mention the confidence and peace of mind these provide during periods, workouts, and daily activities. Several note they're particularly good for teens and lighter flow days. However, common concerns include sizing inconsistencies, with many finding recent purchases run smaller than expected. Some mention the front coverage could be longer, and a few experience issues with leg holes being too tight. Despite sizing challenges, most customers praise the comfort, absorbency, and quality of the product.
86%would recommend these products
FitRated -0.2 on a scale of minus 2 to 2
ComfortRated 4.5 on a scale of 1 to 5
EffectivenessRated 4.5 on a scale of 1 to 5
Keywords
Keywords
Rating
Ratings
Height
Height
How do you use your Leakproof?
How do you use your Leakproof?
Usual Pant Size
Usual Pant Size
808 reviews
  • Rated 5 out of 5 stars
    4 minutes ago
    Beautiful prints!

    I love the prints in this 3 pack! The underwear fits well with just the right amount of stretch. I feel dry (using for light bleeding days so far) and notice no odor.

    SP
    Sarah P.
    Verified Buyer
    Reviewing
    Leakproof UltraThin™ No-Show Bikini 3-Pack
  • Rated 5 out of 5 stars
    9 minutes ago
    Marketing Genius!

    I had been wanting to try the knix period underwear so this was the perfect excuse but the packaging takes this over the top. Kudos to whomever came up with this idea! I love that the underwear matches the book colors and has the cover art on the hip. The underwear also fits well, just the right amount of stretch and keeps me feeling dry/no smell.

    SP
    Sarah P.
    Verified Buyer
    Reviewing
    ACOTAR™ Leakproof Ultrathin™ No-Show Bikini Box Set
  • Rated 5 out of 5 stars
    11 hours ago
    Leakproof UltraThin No-Show Bikini

    Great fit

    AD
    Anastasia d. R.
    Verified Buyer
    Reviewing
    Leakproof UltraThin No-Show Bikini
  • Rated 5 out of 5 stars
    12 hours ago
    Highly recommend

    These are the perfect trifecta: Comfortable, cute,and functional

    JW
    Jennifer W.
    Verified Buyer
    Reviewing
    Leakproof UltraThin™ No-Show Bikini 3-Pack
  • Rated 5 out of 5 stars
    15 hours ago
    Love the Leakproof Ultra Thin No-Show bikini

    I bought 2 leakproof ultrathin no show bikinis for my daughter. She loves them. She said that they are very comfortable and as if you are not wearing anything.

    I bought a beige colour and a rose print one which is very beautiful.

    HG
    Hilka G.
    Verified Buyer
    Reviewing
    Leakproof UltraThin No-Show Bikini
  • Rated 4 out of 5 stars
    16 hours ago
    Love ACOTAR

    They are nice but they fit a little more snug than I would like. Love the designs though.

    RB
    Raylina B.
    Verified Buyer
    Reviewing
    ACOTAR™ Leakproof Ultrathin™ No-Show Bikini Box Set
  • Rated 4 out of 5 stars
    23 hours ago
    Leak Proof

    So comfy and I do not even feel them on.

    DR
    Deanna R.
    Verified Buyer
    Reviewing
    Leakproof UltraThin™ No-Show Bikini 3-Pack
  • Rated 3 out of 5 stars
    Yesterday
    Just okay

    I loved the idea of these and the vibrant colors but I know the graphic will eventually peel off due to use and the sizes run slightly small. I wear a size medium or large normally, I choose size large bc who wants tight period underwear and I am glad it did because there is no way the medium would have been comfortable. Overall I am happy with my purchase because I needed more period underwear but not super impressed. Also the search on this website stinks once I ordered the set a found a cuter acotar set that I would have rather purchased.

    KX
    Kersten X.
    Verified Buyer
    Reviewing
    ACOTAR™ Leakproof Ultrathin™ No-Show Bikini Box Set
  • Rated 5 out of 5 stars
    Yesterday
    5 Stars

    These give me peace of mind and help me feel comfortable. My only frustration is the amount of packaging because each piece was in a separate box inside of a larger box.

    G
    Gabrielle
    Reviewing
    ACOTAR™ Leakproof Ultrathin™ No-Show Bikini Box Set
  • Rated 5 out of 5 stars
    Yesterday
    Love the colors!

    These are the first Knix underwear I’ve purchased and I will definitely be buying more! The quality is high end! So comfortable and I love the colors!

    AE
    Alexis E.
    Verified Buyer
    Reviewing
    ACOTAR™ Leakproof Ultrathin™ No-Show Bikini Box Set
  • Rated 5 out of 5 stars
    2 days ago
    so sexy

    so sexy for leakproof

    LL
    L. L.
    Verified Buyer
    Reviewing
    Leakproof UltraThin™ No-Show Bikini 3-Pack
  • Rated 4 out of 5 stars
    2 days ago
    Booktok came in amazing!

    I love the ACOTAR cross! It was really tight compared to my other Knix products but they have kept up very well.

    SC
    Sadie C.
    Verified Buyer
    Reviewing
    ACOTAR™ Leakproof Ultrathin™ No-Show Bikini Box Set