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Last Call

Leakproof UltraThin No-Show Bikini - Last Call

$18.90 CAD

$27.00

30-70% off

Absorbs about 2.5 super tampons

Invisible under clothes

Moderate protection without the bulk

Machine washable

Jay has 36

Jay has 36" hips and wears a Knix size S

Leakproof UltraThin No-Show Bikini shown front-facing against a light gray background
Jay has 36

Jay has 36" hips and wears a Knix size S

Jay has 36

Jay has 36" hips and wears a Knix size S

Jay has 36" hips and wears a Knix size S

Color: Midnight Limited Edition

Size:

True to Size

•

Size:

Size and Fit Guide

Leakproof Underwear is Sales Tax Free in Canada*
Free Shipping on orders $125+

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.

Delivery Time

For the most up-to-date delivery time estimates, please refer to the shipping timeline at checkout. Delivery timelines vary depending on location and do not include processing times.

Shipping Charges

Orders over $125* CAD = Free Shipping (2-6 business days)

Orders under $125* CAD = $12 CAD Shipping (1-3 business days)

Orders delivering to NWT, Nunavut and Yukon are subject to $20 delivery fee.

*After discounts, before shipping and taxes.

Last Call Return Policy

Sale & Last Call

Our Sale Policy

Here's how returns and exchanges work for sale items.

  • Items discounted 30% or less are eligible for a size exchange or store credit.
  • Items discounted above 30% are final sale. No refunds, store credits, or exchanges.
  • Not sure where your item lands? Chat with us and we'll check for you

Still have questions? View our full policy here.

Rewards Members Earn 18 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

Jay has 36
Jay has 36
Jay has 36

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 805 reviews
Reviews Summary
Customers say these period underwear are comfortable and provide effective protection without the bulk of traditional pads. Many appreciate the soft, buttery fabric that feels like regular underwear and the no-show design under clothing. Users frequently mention confidence during workouts, daily activities, and even swimming. Parents often purchase these for teenage daughters who love the comfort and security they provide. Common feedback includes praise for the absorbency and leak-proof performance. However, several reviews mention sizing inconsistencies, with some finding recent purchases run smaller than previous orders. A few customers note the leg holes can feel tight or that the fit varies between different fabric types.
84%would recommend these products
ComfortRated 4.5 on a scale of 1 to 5
EffectivenessRated 4.5 on a scale of 1 to 5
FitRated -0.2 on a scale of minus 2 to 2
Keywords
Keywords
Rating
Ratings
Height
Height
How do you use your Leakproof?
How do you use your Leakproof?
Usual Pant Size
Usual Pant Size
805 reviews
  • Rated 5 out of 5 stars
    2 weeks ago
    5 Stars

    So happy to get this, and the box set look it comes in omg the ACOTAR collab is amazing and the product high quality

    A
    Addison
    Reviewing
    ACOTAR™ Leakproof Ultrathin™ No-Show Bikini Box Set Thorns & Roses/Mist & Fury/Wings & Ruin/Frost & Starlight/Silver Flames / L
  • Rated 5 out of 5 stars
    22 hours ago
    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 Thorns & Roses/Mist & Fury/Wings & Ruin/Frost & Starlight/Silver Flames / M
  • 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 5 out of 5 stars
    3 days ago
    Comfy comfy

    Very comfortable. I don't really need the period function. But I wanted the ACOTAR collections. Would purchase again if there was another collab. Rating middle ground for effectiveness because I can't tell you

    AR
    Ariana R.
    Verified Buyer
    Reviewing
    Leakproof UltraThin™ No-Show Bikini 3-Pack Ember Fox/Dark Cherry/Autumn Tapestry / L
  • Rated 5 out of 5 stars
    3 days ago
    5 Stars

    Love it. Confortable and good price too.

    H
    Hilka
    Reviewing
    Leakproof UltraThin No-Show Bikini Warm Sand / M
  • Rated 5 out of 5 stars
    3 days ago
    5 Stars

    Bought 2 pairs of leakproof UltraThin No-Show Bikini for my daughter. She loves them . She says that it’s very comfortable and it’s as if you are not wearing anything. 🙂. Love the rose pat- it’s very pretty.

    H
    Hilka
    Reviewing
    Leakproof UltraThin No-Show Bikini Spring Court Bloom / M
  • Rated 5 out of 5 stars
    3 days ago
    5 Stars

    je les adores

    M
    Marie
    Reviewing
    Leakproof UltraThin No-Show Bikini Black / L
  • Rated 5 out of 5 stars
    4 days ago
    Great

    Comfy and effective - so far so good.

    KK
    Kara K.
    Verified Buyer
    Reviewing
    Leakproof UltraThin™ No-Show Bikini 3-Pack Ink That Binds/Midnight/Velaris Night Sky / L
  • Rated 5 out of 5 stars
    4 days ago
    Great product

    This brand it’s amazing, the products are very comfortable, easy to wear, very effective and soft.

    NL
    Nora L.
    Verified Buyer
    Reviewing
    Leakproof UltraThin™ No-Show Bikini 3-Pack Ink That Binds/Midnight/Velaris Night Sky / S
  • Rated 5 out of 5 stars
    4 days ago
    Love!

    So cute! I love them

    MC
    Meghan C.
    Verified Buyer
    Reviewing
    Leakproof UltraThin™ No-Show Bikini 3-Pack Ink That Binds/Midnight/Velaris Night Sky / M
  • Rated 5 out of 5 stars
    4 days ago
    comfortable, no-show leakproof underwear

    This bikini type underwear is smooth and thin, and can't be detected under clothes. It is very comfortable and attractive. The leakproof panel is thin and imperceptible. Recommended for light leaks or light period days.

    RB
    Rebecca B.
    Verified Buyer
    Reviewing
    POS - Leakproof UltraThin™ No-Show Bikini 3-Pack - Last Call
  • Rated 5 out of 5 stars
    1 week ago
    Night court pack

    The night court pack are cute and comfortable.

    MS
    Michaela S.
    Verified Buyer
    Reviewing
    Leakproof UltraThin™ No-Show Bikini 3-Pack Ink That Binds/Midnight/Velaris Night Sky / M

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