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Leakproof UltraThin No-Show Bikini
#1 Daytime Solution
Leakproof UltraThin No-Show Bikini
$27.00
CAD
Buy 3+ Save 15%, Buy 5+ Save 20%
Absorbs about 2.5 super tampons
Invisible under clothes
Moderate protection without the bulk
Machine washable
Size and Fit Guide
How to Measure
In order to select the correct sizing, we recommend you take the following measurements using a soft tape measure. If necessary, ask someone else to help.
Waist
Measure around the narrowest part of your torso, usually just above your belly button. Keep the tape snug and level, but not tight. The number where it meets is your waist measurement.
Hip
Stand with your feet together and measure around the fullest part of your hips and buttocks. Keep the tape level and snug, but not tight. The number where it meets is your hip measurement.
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Leakproof UltraThin No-Show Bikini
Leakproof UltraThin No-Show Bikini
Leakproof UltraThin No-Show Bikini
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Product Description
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.
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How to Choose?
Essential
- • Days you don’t need leak protection. Everyday freshness and moisture wicking.
-
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.
-
about 8-14 tsp
-
about 1.5-3 regular pads
-
about 4-7 super tampons
-
about 1.5-3 menstrual cups
Light
- • Daily freshness. For sweat, discharge, period spotting, or backup protection.
-
about 1-3 tsp
-
about 1-3 pantyliners
-
about 1-3 regular tampons
-
about 0.5 menstrual cups
Moderate
- • For mid-cycle flow, surprise cough or sneeze leaks, or a really sweaty spin class.
-
about 4-8 tsp
-
about 1-1.5 regular pads
-
about 2-4 super tampons
-
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.
-
about 15-20 tsp
-
about 1.5-2.5 super pads
-
about 7-11 super tampons
-
about 2-3 menstrual cups
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FRESH FIX TECHNOLOGY®
Built-in protection that feels like nothing at all.
Our patented 360 LeakSeal™ technology locks in leaks at every edge. The ultra-thin liner absorbs about 2.5 super tampons worth of liquid.
Soft Top Layer
Middle Layer
Leakproof Layer
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How to wash
Knix underwear is 100% reusable and machine washable, just like your regular undies.
Not required. But for best results, you can rinse your leakproof with cold water in the tub or sink before washing.
Machine wash on a cold, gentle cycle with mild detergent.
For their longest life, air drying is best. Hang or lay flat to dry.
Fabric softeners, bleach, ironing, or heat from the dryer.
Total 5 star reviews: 587
Total 4 star reviews: 83
Total 3 star reviews: 50
Total 2 star reviews: 33
Total 1 star reviews: 49
Reviews Summary
Generated by AI from 100 most recent customer reviews
Last updated 2 months ago
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.
86%would recommend these products
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Use Case - Leakproof
Usual Pant Size
802 reviews
- MMMarsha M.Verified BuyerReviewingLeakproof UltraThin No-Show Bikini - Last CallI recommend this productHeight 5'-5'2"How do you use your Leakproof? Light Bladder LeaksUsual Pant Size 6Rated 5 out of 5 stars42 minutes agoLove these.
These work and look great. I live in leggings all the time and they don’t show at all. Love having just that extra comfort too.
- KPKindle P.Verified BuyerReviewingLeakproof UltraThin No-Show Bikini Black / LI recommend this productHeight 5'6-5'8"Usual Pant Size 12Rated 5 out of 5 stars23 hours agoSaved my pickleball game!
Leakproof undies work well for giggles and athletic pursuits. I sweat too much for leakproof pads to stick in place. Real game changer.
- CTConcetta T.Verified BuyerReviewingLeakproof UltraThin No-Show Bikini 3-Pack - Last Call Eucalyptus/Rose Quartz/Rosewood / LI recommend this productRated 5 out of 5 starsYesterdayLove them
I always look for the packs and I love the colors. I wish there were colors and patterns like this in the cotton. This is a great set.
- GCGary C.Verified BuyerReviewingLeakproof UltraThin No-Show BikiniI recommend this productHeight <5'5"Usage Light Bladder LeaksSize Purchased - Underwear & Apparel LUsual Pant Size 12Rated 5 out of 5 stars1 week agoWorth every penny
Much more comfortable than a panty liner
KKnix1 week agoHey Gary!
Thanks so much for taking the time to review our Leakproof UltraThin No-Show Bikini! We're thrilled to hear you're loving the comfort over traditional options.
Team Knix
- JWJess W.Verified BuyerReviewingLeakproof UltraThin No-Show BikiniI recommend this productUsage SweatSize Purchased - Underwear & Apparel SUsual Pant Size 2Rated 5 out of 5 stars1 week agoPerfect
Wear to Pilates all
The time best panties ever !
KKnix1 week agoHey Jess!
This is amazing! We're so happy our Leakproof UltraThin No-Show Bikini is your go-to for Pilates. Thanks for making us your workout partner!
Team Knix
- CRchris r.Verified BuyerReviewingLeakproof UltraThin No-Show Bikini 3-Pack - Last Call Eucalyptus/Rose Quartz/Rosewood / MI recommend this productRated 5 out of 5 stars2 weeks agoLeakproof bikini
Light weight.no show. Works for leak proof. Very happy. I wished you offered more 3 packs.
KKnix2 weeks agoHey Chris!
Thanks so much for the amazing review! We're thrilled you're loving the lightweight, no-show comfort and leakproof protection. We'll definitely keep your 3-pack feedback in mind!
Team Knix
- LALisa A.Verified BuyerReviewingLeakproof UltraThin No-Show BikiniI recommend this productHeight <5'5"Usage Primary Period ProtectionPant Size Purchased SRated 5 out of 5 stars2 weeks agoMore Colors!
I love these moderate leak underwear; they're absolutely perfect for the bookend days of my period, and I love that they keep coming out with new patterns and colors! :)
KKnix2 weeks agoHey Lisa!
This is amazing! We're so happy you're loving the Leakproof UltraThin No-Show Bikini for those bookend days. We love bringing you new patterns and colors too! 💖
Team Knix
- LRLisa R.Verified BuyerReviewingLeakproof UltraThin No-Show Bikini Black with White Polka Dot / LI recommend this productHeight 5'6-5'8"Pant Size 10Pant Size Purchased LRated 5 out of 5 stars2 weeks agoComfy fit
Love the polka dot pattern.
KKnix2 weeks agoHey Lisa!
Thanks so much for the review! We're thrilled you're loving the comfy fit and polka dot pattern on your UltraThin No-Show Bikini!
Team Knix
- CFClara F.Verified BuyerReviewingLeakproof UltraThin No-Show BikiniI recommend this productPant Size Purchased MRated 5 out of 5 stars2 weeks agoSo confortable
Very confortable and leak proof
KKnix2 weeks agoHey Clara!
Thanks so much for taking the time to review our Leakproof UltraThin No-Show Bikini! We're so happy to hear you're loving the comfort and protection!
Team Knix
- JLJacinthe L.Verified BuyerReviewingLeakproof UltraThin No-Show Bikini - Last Call Rose Noir / XLI recommend this productHeight <5'5"Pant Size 18Pant Size Purchased XLRated 5 out of 5 stars2 weeks agoJe ne porte plus que ça
Depuis que je les ai essayées, ce sont les seuls sous vêtements que je porte. J’ai du m’ajuster pour la taille car après avoir été portées quelques fois, les culottes ont tendance à étirer. J’ai dû prendre une taille en-dessous de ce que je porte dans les autres marques.
- LLLisa L.Verified BuyerReviewingTeen Leakproof UltraThin No-Show Bikini 3-PackI recommend this productHeight <5'5"Size Purchased - Knixteen Underwear SRated 5 out of 5 stars2 weeks agoGreat fit, great teen protection
My daughter loves hers and wanted more of them. I’d highly recommend this for teen girls.
KKnix2 weeks agoHey Lisa!
Thanks so much for this sweet review! We're thrilled your daughter loves her Teen Bikinis and that you'd recommend them. There's nothing better than happy teens feeling confident!
Team Knix
- TFTracy F.Verified BuyerReviewingLeakproof UltraThin No-Show BikiniI recommend this productHeight 5'6-5'8"Pant Size 4Usage Light Bladder LeaksPant Size Purchased SRated 5 out of 5 stars2 weeks agoGreat
Works and comfy
KKnix2 weeks agoHey Tracy!
Thanks so much for taking the time to review our Leakproof UltraThin No-Show Bikini! We're so happy to hear you're loving the comfort and performance!
Team Knix
