Bikini First Line - Next Gen Iron-Underwear-TomboyX

First Line Leakproof Bikini

38 Reviews

$22

Color Next Gen Iron

Size

Color

It's all in the hips

For the best fit, pick your size based on your hip measurement.
Body measurement in inches

Size	Waist	Hips
XS	26-27.5"	33-34"
S	28-29.5"	35-37"
M	30-31.5"	38-40"
L	32.5-34"	41-43"
XL	35-37.5"	44.5-46.5"
2X	38.5-42"	48-50"
3X	43-45"	51.5-53.5"
4X	46-48"	55-56"

For more detailed information, please see our Fit Guide page.

How to measure your hips

Stand on a level surface, feet together without shoes.
Measure around the fullest part of your hips and bottom - this is usually 7-9" below your natural waistline.
Keep the tape measure parallel to the floor, and don't pull too tight.

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Like the arid high plateaus of the Gobi desert, First Line keeps you dry and comfortable while you're on the move. With built in leak protection for light days and incontinence you can say goodbye to pads, tampons, and menstrual cups.

Looks and fits just like regular TomboyX Underwear
Holds 8 tsps of liquid
Odor-resistant
Machine wash cold in a mesh bag, line dries overnight. Avoid machine drying.
95% OEKO-TEX®-certified cotton, 5% spandex

HUMAN-FRIENDLY

Our cotton underwear is Oeko-tex 100 certified—a highly-regarded international standard for non-toxic fabrics.

Stock Up & Save! Buy 3+ of any undies and/or bras & get 10% off. Buy 5+ and get 15% off.

Living Wage factories

Ethically produced in women-owned factories that pay living wages.

fit-tested for every body

Obsessively fit-tested on real people, sizes XS-4X.

Love at first wear

If you don't love them, your first pair is on us.

eco-friendly process

Sustainably harvested materials and earth-conscious production.

Live the X

Join the movement. Follow @TomboyX and tag us in your pics for a chance to be featured.

Fabrics & Technology

Cotton

Our classic soft jersey knit holds its shape after many wear and care cycles.

Shop Cotton

MicroModal

The luxurious companion to cotton. Supersoft, breathable and stretches to meet you.

Shop Micromodal

Traveler

Quick-drying, durable and ultralight performance fabric. Anti-bacterial and anti-microbial.

Shop Traveler

First Line Leakproof

Your first line of defense — our classic cotton armed with leak protection for light period days and incontinence.

Shop First Line