Flow Bikini - Period Undies
Flow Bikini - Period Undies
Flow Bikini - Period Undies
Flow Bikini - Period Undies
Flow Bikini - Period Undies
Flow Bikini - Period Undies
Flow Bikini - Period Undies

Flow Bikini - Period Undies -Regular price $33.00

Tax included.
Only 33 items in stock!

Explore the icons to learn about this product’s positive impact

Sustainable Materials

+ Our undies are made with a sustainable fibre called Tencel, which is produced from the wood pulp of FSC certified Eucalyptus trees in a non-toxic closed-loop process. Learn More

Resources Saved

+ Tencel uses use less water, carbon and chemicals compared to cotton and bamboo, saving finite planetary resources. Learn More

Carbon Positive

+ We are a certified Carbon Positive business, meaning we buy 1.5 times more carbon offsets than we produce. Learn More

Ethically Made

+ Our undies are made in BSCI certified factories in China where workers are paid 60% above the living wage. Learn More


+ For every purchase, we donate one pair of undies to someone in need. Learn More

Socially Regenerative

+ We are a certified Social Enterprise partnering with the National Homeless Collective to provide workplace training for those experiencing or at further risk of homelessness. Learn More

Recycling Hub

+ We take back any brand of underwear and recycle them, so that they can be repurposed and diverted from landfill. Learn More

Our Flow Undies are the perfect companion to a zero-waste empowered period, bought once, to then last for years.

We chose regenerated eucylyptus Tencel for our Flow period undies because:

  • It is the most absorbent fibre available
  • It rapidly absorbs moisture and very quickly spreads it across its nanofibre structure, which means you will feel drier
  • It also holds 50% more fluid than cotton
  • Thermoregulating - it naturally has a thermal control to keep you cool
  • Incredibly soft and gentle against the skin
  • Naturally antibacterial without the use of toxic chemicals
  • Highly breathable
  • Made from a renewable fast growing source, eucylptus trees

These qualities mean that we can engineer period undies without bulk. We use layers of Tencel in key areas to maximise aborption and still feeling light. 

They inclued a waterproof, breathable layer made from Oeko-Tex certified toxin free PU laminated Tencel. It extends from the front gusset up to the back waist, ensuring no leaks when sitting and lying down.

Our Flow undies as a sustainable solution, but also one that reconnects you to your body and away from commercial plastic mass market products. 

One pair of undies can be worn all day.

And most importantly, choosing these period undies means another person that cannot afford them is getting period undies for free one-for-one, let's erase period poverty. 


TENCEL™ is an eco-friendly fiber made from responsibly sourced wood pulp. The wood pulp is dissolved in a closed-loop process with a non-toxic organic solvent, then the solution is forced through tiny holes in order to create an absorbent biodegradable fiber that feels softer and lighter than cotton.
  • Wilma is 180 cm and wears a small in black
  • Safa is 170 cm and wears a large
  • If in doubt, size up one size
View the size guide below

Customer Reviews

Based on 10 reviews
Slightly underwhelmed

I read all the reviews and was excited about my purchase, but am a little underwhelmed.
Whilst the gusset lining goes all the way to the back, it lacks coverage at the front. I will not be able to use these at night, as I tend to sleep ony front and there is no lining. Even for day wear I had to position them pulled high at the front and low at the back, just to have adequate coverage at the front.
They are super absorbent though which is impressive.
Unfortunately there is a small hole in one of the pairs that I didn't notice until after I'd put them on, and is likely to get bigger and render them unusable before too long.

Tanya E.
LIfe changing

This is my first foray into period underwear and I am very happy. Comfortable to wear, easy to care for and easier on the planet. I have a light flow and I can wear one pair for a day with no problem. Have now purchased three pairs which I can wash and dry in rotation. Thank you Underwear for Humanity.

Super Comfy

These undies are super comfy and a great fit (true to size).
They don’t have that gross bulky/nappy feeling that some other brands have in the bum area.
I was a little concerned at first about how low the front gusset sits on me but I have had no problems at all.
The crinkly noise other have mentioned in reviews went away with the initial wash.
I am super happy with my purchase and I love supporting this business and their great cause.

First time user

It has taken me some time to try period undies (I'm 45) and I'm now a total convert. I can't comment on other brands but these are such a revolution. Given my trepidation, I only wore them day 3-6 day and night, but I'm confident I'd have no issues from day 1 next time. (My period is fairly light). I have since purchased 3 pairs in total and a further 3 pairs for my mum for some light incontinence. She loves them too. I'm a size 14 -16 in bottoms and the 14 are perfect. They wash well and dry quicker than expected. The faint rustling noise does go away with a couple of washes. The feel good factor in terms of donations and the environment is also a selling point for me.

Thorn Raven
Most comfortable period undies I have worn

Wearing these for the first time today, so far: super comfortable and absorbing well, and compared to other period undies I have worn I am loving how light and non-bulky they are.

You may also like