Size	AU/NZ	UK	US
XS	8A 8B 10A	30A 30B 32A	30A 30B 32A
Small	8DD 10B 10C 10D 10DD 12A 12B	30DD 32B 32C 32D 32DD 34A 34B	30DD 32B 32DD 32C 32D 34A 34B
Medium	12C 12D 12DD 12E 14A 14B	34C 34D 34DD 34E 36A 36B	34C 34D 34DD 34DDD 36A 36B
Large	14C 14D 14DD 14E 16A 16B 16C	36C 36D 36DD 36E 38A 38B 38C	36C 36D 36DD 36DDD 38B 38C
XL	16D 16DD 16E 18A 18B 18C 18D	38D 38DD 38E 40A 40B 40C 40D	38D 38DD 38DDD 40A 40B 40C 40D

Size	AU Size	UK Size	Waist (cm)
XS	04-06	00-02	60
Small	08-10	04-06	64
Medium	12-14	08-10	68
Large	16-18	12-14	72
XL	20-22	16-18	76
2XL	24-26	20-22	80

Size	Waist (cm)	Waist (in)
2XS / (Size 4/8)	53-56	21-22
XS / (Size 8/12)	57-66	23-26
Small	67-76	27-30
Medium	77-86	31-34
Large	87-97	35-38
Extra Large	98-107	39-42
2XL	108-115	43-45
3XL	116-125	46-49
4XL	126-133	50-52
5XL	134-143	53-56
6XL	144-150	57-59

Size	Waist (cm)	Waist (in)
4XS (Age & Size 3-4)	40-44	15-17
3XS (Age & Size 5-6)	45-51	18-20
2XS (Age & Size 7-8)	52-59	21-22
XS (Age & Size 9-11)	60-69	23-26
S (Ages & Size 12-14)	70-76	27-30

SHOP MEN'S SHOP WOMEN'S SHOP JUNIORS

Love them or
they're free

Women's Period Bikini Brief - Bamboo Underwear - Model:Armani

Armani is 170cm tall, 63m waist, wearing a size XS

Women's Period Full Brief - Bamboo Underwear

Armani is 170cm tall, 63m waist, wearing a size XS

Women's Period Bikini Brief - Bamboo Underwear - Model:Chloe

Chloe is 168cm tall, 65m waist, wearing a size XS

Min Bulk, Max Absorbency

Sweat-Wicking Bamboo Material

Hypoallergenic

Period
Bikini Brief

Name: Women's Period Bikini Brief
Brand: Step One
SKU: BIBPM-XS-10063-1
Price: 33.0 AUD
Availability: InStock

$33 ea

Low as $23 with packs

Min Bulk, Max Absorbency

Sweat-Wicking Bamboo Material

Hypoallergenic

Coverage

Color

✓

Black

✓

Nude

Absorbency

✓

Moderate

✓

Heavy

Period Underwear Size Guide

Size	Waist (cm)	Hips (cm)	Waist (in)	Hips (in)
XS	65–70	82–86	25.5–27.5	32.5–34
S	70–74	86–91	27.5–29	34–36
M	74–79	91–96	29–31	36–38
L	79–84	96–101	31–33	38–40
XL	84–89	101–106	33–35	40–41.5
2XL	89–94+	106–110+	35–37	41.5–43.5

Size

Find My Fit →

✓

2XL

Variant

Packs

✓

Single
$33 ea.

✓

4 Pack
$31 ea. Save $8

✓

7 Pack
$29 ea. Save $28

✓

15 Pack
$23 ea. Save $150

Why these are life changing

Integrated absorbent core

Mid-rise with classic bikini silhouette

Moisture-wicking and odour-resistant

First Pair Guarantee - Love them or they're free!

Frequently purchased together...

SmoothFit
Padded Bra Espresso-Tini

$39.00

SmoothFit
Padded Bra Light Beige

$39.00

SmoothFit
Thong Espresso-Tini

$25.00

Description

The Period Bikini Brief is your everyday go-to. Slim, supportive, and designed to look and feel like our best-selling Bikini Briefs, this style absorbs without adding bulk. From desk days to weekend plans, it’s breathable, soft on skin, and engineered for real-life performance.

Integrated absorbent core
Mid-rise with classic bikini silhouette
Soft FSC-certified bamboo viscose
Moisture-wicking and odour-resistant
Tested for comfort, durability, and long wear

Fit & Fabric

Main fabric: 95% viscose (bamboo), 5% elastane
Inside gusset layer: 100% merino wool
Absorbent layer: 70% polyester, 30% cotton with TPU laminate

Shipping

We aim to dispatch your order 4-5 business days after placing your order.

All orders to Australian addresses are FREE!

General shipping times are below:

NSW, VIC & QLD = approx. 1-3 business days after dispatch.

WA, NT, TAS = approx. 2-4 business days after dispatch.

We offer international shipping to selected countries, which is shown at checkout. International shipping may vary based on local fulfilment.

Read our more comprehensive shipping times via the link here

30 Day First Pair Guarantee

We are so confident you'll love your Step Ones, we'll give you a FULL REFUND on your FIRST PAIR if you don't like them for whatever reason.

In stock

Welcome to our SmoothFit range

Your new favourites

Crafted with care and designed for maximum comfort, these underwear are a game-changer in the world of intimates. Made from bamboo viscose, a natural and eco-friendly fabric, our ribbed seam free underwear offers a seamless and irritation-free experience.

Say goodbye to muffin top

The seamless waist construction eliminates any irritating seams that could dig into your skin, making these underwear ideal for everyday wear, workouts, or lounging. The bamboo viscose fabric is incredibly soft to the touch and naturally moisture-wicking, keeping you fresh and dry throughout the day.

Undies that love the planet

Bamboo is a renewable resource that grows rapidly and requires minimal water and pesticides. It also has natural anti-bacterial properties, reducing the need for chemical treatments. By choosing our bamboo viscose underwear, you're making a conscious decision to support eco-friendly practices.