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The Everyday Bikini features an invisible leak-resistant lining in the gusset. Our lining is thin and breathable to help you feel comfortable and dry.
replace a panty liner
back up a tampon
Outer: 75% Nylon 25% Spandex
Lining: 100% Cotton
Lining: 95% Cotton 5% Spandex
See all FAQs
What is bikini style underwear?
The bikini undies by Proof feature a mid-rise fit, high cut leg opening, and moderate booty coverage, all in a comfortable stretch fabric that moves with your body.
What is the difference between brief and bikini underwear?
The bikini features a high-leg opening and narrow sides, with a mid-rise and moderate back coverage. The brief is designed with wider sides, lower rise, and moderate back coverage.
Is this underwear environmentally friendly?
Proof undies are designed to be better for you, and the environment! Single-use plastic period products like tampons and pads end up in landfills and oceans, where they pose a serious threat to wildlife. By switching to Proof, you help to reduce single-use plastic waste.
Proof’s patented Leak-Loc™ technology protects against all of life’s leaks, both big and small. Our undies hold up to 10 teaspoons (that’s 5 full tampons worth!) of liquid. We craft our pairs with rigorously-tested materials, to ensure the highest quality care *down there*.
This is really (really) leakproof underwear
A classic silhouette with discreet leak protection
Super absorbent and powerful leak protection
Travel laundry woes, begone.
60 day leak free guarantee
FREE SHIPPING on all orders OVER $50
With a pair for every flow, you’ll be able to find your Proof™-perfect fit.
Our Patented Leak-Loc™ technology keeps you leak-free learn more
Proof™ provides serious protection from bladder leaks, without added bulk.
Discrete protection with room to accommodate your growing bump.
Designed with new moms in mind, leak protection without the bulk.
Go ahead, break a sweat. Our moisture-wicking fabric also reduces odor.
Undercover protection for every day of the week.
Perfect for daily discharge, Proof™ keeps you fresh and dry.
For in-between days, these undies keep you spotless all day long.
Holds up to 1 Light Tampon or Panty Liner
panty liner replacement
Holds up to 1 Regular Tampon or 2 Teaspoons
light period leaks
Holds up to 3 Regular Tampons or 6 Teaspoons
moderate period leaks
light bladder leaks
replace or back up a tampon, pad, or cup
Holds up to 4 Regular Tampons or 8 Teaspoons
moderate bladder leaks
heavy period leaks
replace a pad
replace or back up a tampon or cup
Holds up to 5 Regular Tampons or 10 Teaspoons
maximum overnight period protection
Your hip and waist measurements are the most important size when finding the perfect fit.
Measure around your body as shown.
Find your waist measure by leaning over to one side. Where your body naturally creases is your where you will place the tape. Measure parallel to the ground.
For your hip measurement, turn to the side and locate the fullest part of your booty. Place the tape around your body, parallel to the floor, around the widest and fullest part of your hips and tush.
If your measurements fall into different size categories, your hip measurement will be most accurate.