The Brief Starter Kit

The Underdays Starter Kit

£48

Style :

Brief Mix Thong

Size :

Size guide

XS S M L XL XXL

Product fit

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Free UK Delivery over £60+
Free UK Returns & Exchanges

Complete the set

Meet the Underdays Brief Starter Kit — three of our bestselling Everyday Briefs in one set. Full coverage, zero compromise: each pair is cut for a clean, smooth silhouette in luxuriously soft, breathable TENCEL™ Modal. Paired with our Scuba Cloud Pouch, designed to go everywhere you do. Everything you need to start an intentional underwear drawer.

UNDERskin™: 100% biobased synbiotic technology, supports your skin's natural microbiome, lasts up to 40 washes. Data provided by HeiQ based on testing conducted on other materials.

Crafted from buttery-soft, breathable TENCEL™ Modal — designed for all-day comfort.

An antimicrobial gusset designed to support your body — from daily wear to your most active days.

Designed to flatter every body and hold its shape wash after wash.

Comes in our Scuba Cloud Pouch — designed to go everywhere you do.

•92% Micromodal, 8% Elastane
•Gusset: 92% Tencel Micromodal, 8% Elastane
• UNDERskin™: Prebiotics + probiotics infused in the fabric transfer to your skin on contact, supporting a balanced, healthy-looking microbiome. 100% biobased. Powered by HeiQ Skin Care™.
•All fabrics are OEKO-TEX certified (SH015 210990 Testex)

•Care: To preserve the HeiQ Skin Care™ treatment, wash at 30°C on a gentle cycle. The synbiotic technology is designed to last up to 40 home washes. Data provided by HeiQ based on testing conducted on other materials.
We also recommend to wash your Underdays in a mesh laundry bag. Air-dry flat in a shaded area. Do not bleach. Do not iron or tumble dry.

  • We offer both Next Day Delivery and Standard Delivery

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Your underwear deserves better

You care about your skin, your wellness, your rituals. We’re pioneering care for your most intimate parts.

Powered by UNDERskin™

Prebiotics and probiotics, infused into the fabric, transferring to your skin all day. Supports your microbiome. Strengthens your skin barrier. Promotes a healthier appearance. 100% biobased. Developed in Switzerland.

Twice the softness of cotton

Our underwear is made from TENCEL™ Modal—sustainably derived from trees and twice as soft as cotton. Gentle on the skin and made to feel like nothing at all.

Let your ____ breathe freely

TENCEL™ fibers are unfavorable for bacteria growth. They wick away moisture and keep you fresh through the day. Designed to help reduce the risk of unwanted infections.

OEKO-TEX Certified

OEKO-TEX® certified —clean, non-toxic with no harmful substances

Set apart by design

High Street Brand

TENCEL™  modal antimicrobial fabric derived from trees

Synthetics

Prebiotics + probiotics infused in the fabric for a healthier skin microbiome

Tested by real women, with over 1,000 five-star reviews

Engineered for optimal airflow and breathability

Traps moisture

A 2cm extra-long gusset for everyday protection

Soft leg elastics designed to eliminate digging in

Harsh seams

Product details