Home/
All Underwear

All Underwear

From ultra-soft fabrics and seamless styles to super absorbent underwear, you’re covered 24/7/365. Take our Leakproof Quiz to find your perfect pair.

Ultra

Absorbs 7-9 super tampons Heavy

Absorbs 3-6 super tampons Moderate

Absorbs 2-3 super tampons Light

Absorbs 1-3 regular tampons Essential

No absorbency Teen Underwear

76 Items

Best Seller

Ultra Leakproof Zones+ Bikini

$36.00 USD

Save up to 20%

Color: Black

BlackWarm SandRose WaterDark Teal

Best Seller

Ultra Leakproof Zones+ High Rise

$39.00 USD

Save up to 20%

Color: Warm Sand

Warm SandBlackRose WaterDark Teal

Best Seller

Super Leakproof® Dream Short

$42.00 USD

Save up to 20%

Color: Black

BlackWarm SandMidnightLilac

Best Seller

Super Leakproof® No-Show Bikini

$29.00 USD

Save up to 20%

Color: Lilac, limited edition

LilacBlackWarm SandDune

Best Seller

Super Leakproof® No-Show Boyshort

$29.00 USD

Save up to 20%

Color: Black

BlackWarm SandSableMidnight

Best Seller

Super Leakproof® No-Show French Cut

$32.00 USD

Save up to 20%

Color: Lilac, limited edition

LilacBlackWarm SandDune

Best Seller

Super Leakproof® No-Show High Rise

$34.00 USD

Save up to 20%

Color: Buttercup, limited edition

ButtercupBlackWarm SandDune

Best Seller

Leakproof No-Show Thong

$27.00 USD

Save up to 20%

Color: Warm Sand

Warm SandBlackDuneCavassa

Best Seller

Leakproof UltraThin No-Show Bikini

$25.00 USD

Save up to 20%

Color: Rose Water

Rose WaterBlackWarm SandSola

Gabrielle has 48” hips and wears a Knix size XXL

Best Seller

Leakproof Cotton Bikini

$23.00 USD

Save up to 20%

Color: Pepper

PepperBlackRose WaterMidnight

Leakproof UltraThin No-Show French Cut

$27.00 USD

Save up to 20%

Color: Lilac, limited edition

LilacBlackWarm SandSola

+13

Best Seller

Leakproof UltraThin No-Show High Rise

$29.00 USD

Save up to 20%

Color: Buttercup, limited edition

ButtercupBlackWarm SandSola

Restocked

Leakproof CoreLove High Rise

$38.00 USD

Save up to 20%

Color: Black

Black

Best Seller

Leakproof Cotton Boybrief

$35.00 USD

Save up to 20%

Color: Rose Water

Rose WaterBlackMidnightMushroom

Luxe Modal Leakproof Sleep Boxer

$38.00 USD

Save up to 20%

Color: Black

BlackDark CherryMushroom

Light Leakproof No-Show Thong

$20.00 USD

Save up to 20%

Color: White

WhiteBlackWarm SandDune

Light Leakproof UltraThin No-Show Thong

$23.00 USD

Save up to 20%

Color: Lilac, limited edition

LilacBlackWarm SandSola

Light Leakproof Gossamer Lace Thong

$24.00 USD

Save up to 20%

Color: Black

BlackDark CherryOlive

Light Leakproof No-Show High Rise Thong

$24.00 USD

Save up to 20%

Color: Sola

SolaBlackWarm SandWhite

Best Seller

Light Leakproof No-Show Bikini

$22.00 USD

Save up to 20%

Color: Warm Sand

Warm SandBlackDuneCavassa

+10

Claire has 35" hips, 24" waist and wears a Knix size S

Light Leakproof No-Show Mesh Bikini

$22.00 USD

Save up to 20%

Color: Black

Black

Light Leakproof Gossamer Lace Bikini

$26.00 USD

Save up to 20%

Color: Dark Cherry, limited edition

Dark CherryBlackOlive

Best Seller

Light Leakproof No-Show Boyshort

$22.00 USD

Save up to 20%

Color: Buttercup, limited edition

ButtercupBlackWarm SandDune

Best Seller

Light Leakproof No-Show French Cut

$24.00 USD

Save up to 20%

Color: White

WhiteBlackWarm SandDune

+11

Leakproof Logo Rib Modal French Cut

$28.00 USD

Save up to 20%

Color: Grey

GreyBlackWhite

Light Leakproof Gossamer Lace French Cut

$28.00 USD

Save up to 20%

Color: Buttercup, limited edition

ButtercupBlackWhiteOyster

Best Seller

Light Leakproof No-Show High Rise

$26.00 USD

Save up to 20%

Color: Lilac, limited edition

LilacBlackWarm SandDune

Light Leakproof No-Show Mesh High Rise

$26.00 USD

Save up to 20%

Color: Oyster, limited edition

OysterBlackLilacWhite

Esther has 38" hips and wears a Knix size M

Leakproof Logo Rib Modal Boxer Brief

$38.00 USD

Save up to 20%

Color: White

WhiteBlackGrey

Amber has 38" hips and wears a Knix size M

Essential No-Show Thong

$18.00 USD

Save up to 20%

Color: Rose Water

Rose WaterBlackWarm Sand

New

Essential No-Show Thong 5-Pack

$75.00 USD

Color: Pastels, limited edition

Pastels

New

Essential Mesh Thong

$18.00 USD

Save up to 20%

Color: Lilac, limited edition

LilacBlackWhiteOyster

New

Essential Gossamer Lace Thong

$18.00 USD

Save up to 20%

Color: Buttercup, limited edition

ButtercupBlackWhiteOyster

Essential No-Show High Rise Thong

$22.00 USD

Save up to 20%

Color: Warm Sand

Warm SandBlack

Essential No-Show Bikini

$20.00 USD

Save up to 20%

Color: Warm Sand

Warm SandBlackRose Water

New

Essential No-Show Bikini 5-Pack

$85.00 USD

Color: Pastels, limited edition

Pastels

New

Essential Mesh Bikini

$20.00 USD

Save up to 20%

Color: White

WhiteBlackLilacOyster

New

Essential Gossamer Lace Bikini

$20.00 USD

Save up to 20%

Color: Black

BlackButtercupWhiteOyster

Kalle has 38" hips, 29" waist and wears a size M

Essential No-Show Boyshort

$20.00 USD

Save up to 20%

Color: Rose Water

Rose WaterBlackWarm Sand

Essential No-Show French Cut

$22.00 USD

Save up to 20%

Color: Black

BlackWarm Sand

New

Essential Gossamer Lace French Cut

$22.00 USD

Save up to 20%

Color: Oyster, limited edition

OysterBlackButtercupWhite

Essential No-Show High Rise

$24.00 USD

Save up to 20%

Color: Warm Sand

Warm SandBlackRose Water

New

Essential No-Show High Rise 5-Pack

$105.00 USD

Color: Pastels, limited edition

Pastels

Best Seller

Shaper High Rise Briefs

$45.00 USD

Save up to 20%

Color: Black

BlackWarm SandSola

Shortie Thigh Saver® 4”

$36.00 USD

Save up to 20%

Color: Dune

DuneBlackWarm SandCavassa

Isabelle has 40" hips and wears a Knix size M

Best Seller

Thigh Saver® 6”

$36.00 USD

Save up to 20%

Color: Sola

SolaBlackWarm SandCavassa

Mix & Match Sets Feature Tile - Jan 2025

Best Seller

Leakproof Thigh Saver® 6”

$39.00 USD

Save up to 20%

Color: Sable

SableBlackWarm SandDune

Leakproof Contour Thigh Saver® 6”

$46.00 USD

Save up to 20%

Color: Warm Sand

Warm SandBlackSola

Luxe Modal Thigh Saver® 6"

$36.00 USD

Save up to 20%

Color: Savanna, limited edition

SavannaBlack

Tamiah has 38.5” hips and wears a Knix size M

Lace Thigh Saver® 6"

$36.00 USD

Save up to 20%

Color: Toasted, limited edition

ToastedBlackSolaCitron

Tsanna has 34.5" hips and wears a Knix size S

Leakproof Thigh Saver® 10”

$44.00 USD

Save up to 20%

Color: Sola

SolaBlackWarm Sand

New

Reusable Snap Leakproof Pads - Overnight (3-Pack)

$40.00 USD

Color: Black

Black

New

Reusable Snap Leakproof Pads - Regular (3-Pack)

$36.00 USD

Color: Black

Black

Leakproof Cotton High Rise

$27.00 USD

Save up to 20%

Color: Black

BlackRose WaterMidnightMushroom

Astrology Collection Leakproof UltraThin Bikini

$25.00 USD

Save up to 20%

Color: Virgo, limited edition

VirgoAriesTaurusGemini

Sale

Heavy Period Kit - High Rise

From $160.20 USD

Save $17

Color:

Sale

Heavy Period Kit - Bikini

From $142.20 USD

Save $15

Color:

Best Seller

Leakproof Cotton 4-Pack - Bikini

From $82.80 USD

Save $9

Color:

Sale

Mixed Period Kit - Boyshort

From $129.60 USD

Save $14

Color:

Sale

Mixed Period Kit - Bikini

From $129.60 USD

Save $14

Color:

From ultra-soft fabrics and seamless styles to super absorbent underwear, you’re covered 24/7/365.

Your leakproof questions, answered.

Our Leakproof technology features a built-in absorbent liner. Depending on the style you choose, the absorbency can range from about 1-17 tsp of liquid. The result? Confident protection from sweat, discharge, periods, and light bladder leaks.

A gusset is essentially a liner. It’s where you’ll find our leakproof technology. It’s built into the crotch section of the underwear.

Coverage at Knix comes in all shapes and sizes. If we’re talking about silhouettes, we go all the way from thongs to boxers.

We also offer high rise styles, like the Leakproof UltraThin No-Show High Rise, that sits just above the natural waist and gives full coverage through the stomach, hip & bum.

For extra liner coverage, look for undies that have an “extra-long liner” (usually 10”-14”), like in our Dream Short. And our Ultra Zones+ also have full bum coverage, too.

Have a suggested style or coverage? Just let us know. We love the feedback!

Many people refer to them as period underwear or period panties. But leakproof underwear covers you for all of life’s leaks, including periods (even your heaviest flows), sweat, light bladder leaks, postpartum, and discharge.