Classic Bikini

holds OVER 4 tampons' worth

Our bestselling Bikini offers full coverage and protection, keeping you fresh 'n' dry when you need it most. 

Bikini features a soft lace trim that keeps your undies looking so cute, you might even forget you're on your period!

Our bestselling Bikini offers full coverage and protection, keeping you fresh and dry always

Bikini features a soft lace trim that keeps your underwear looking so cute, you might even forget you're on your period!

Our bestselling Bikini offers full coverage and protection, keeping you fresh and dry all the time. 

Bikini features a soft lace trim that keeps your undies looking so cute, you might even forget you're on your period! 

  • Wear For Up To 12 Hours 
  • Holds Up To 25ml, Or 4-5 Tampons' Worth 
  • For Periods, Leaks & Incontinence 
  • For Day & Night

Bikini - Heavy Absorbency


Holds 4-5 tampons' worth, or 20-25ml of blood.

Wear alone for up to 12 hours.


Interior: 50% Modal 50% Organic Cotton, Exterior: 82% Nylon 18% Lycra, Trim: 100% Polyester



Give 'em a quick rinse 🚿


Chuck 'em in a mesh laundry bag before popping them into the machine on a cold wash 👌🏽


Hang to dry outside or inside! ✌🏿

PS: Don't use bleach or fabric softener ⚠️

Customer Reviews

Based on 74 reviews
Flow: Super Heavy, Heavy
Products used: Menstrual cup
Wonderful! If a little uncomfortable...

I received them half-way through my period so I have yet to trial them at the height of my endometriosis, but I was really happy the result. They fit awkwardly across my back-side and gape a little, but after an hour or so of wearing them I didn't notice it too much. They're easy to clean and there was no smell!

Flow: Super Heavy
Products used: Tampons, Disposable pads
Not quite leakproof

Ok. Doesn’t feel as secure as I would expect and leaks a bit. I followed the measurements guidelines and bought a L (I normally buy M for clothing).
Otherwise they are comfortable to wear, easy to wash and no nasty smell :)

Flow: Super Heavy
Products used: FLUX Undies, obvs!, Cloth pads
I was very sceptical, but...

... I bought a couple of pairs of these to test out, thinking I would absolutely hate them and feel dirty and smelly wearing them all day. I've had two periods since buying Flux Undies and what can I say? Genuinely never turning back and am sitting here annoyed with myself that I didn't switch sooner! I have a heavy flow for a couple of days and while I am sure the panties could handle my flow, I use a washable sanitary towel over my Flux Undies on the worse days to have myself covered at work. The only complaint, which isn't really a complaint as such, is that the pants take FOREVER to dry after washing (understandably, I guess), so I will need to stock up on many more pairs to have enough to get me through the dark days of periods every month. And cheap they ain't! But a few pairs a month means that in a couple of months I will have enough of them to be a-ok.

Flow: Light
Products used: FLUX Undies, obvs!, Tampons, Disposable pads, Cloth pads
I am delighted

I’m so happy I bought these. I was unsure whether to get these or another American brand. In the end the better price and shipping costs made me choose these. They are true to size (and not super low waisted like a lot of knickers these days). The leg holes are snug but I suppose that prevents leaks. I was as comfortable, if not more so, in these for a day As I would be in my ‘normal’ knickers. I plan to get more and stop using uncomfortable and wasteful sanitary products altogether.

Flow: Heavy
Products used: FLUX Undies, obvs!, Menstrual cup
I couldn't be more pleased

These underwear rock! No more leaks or worry. Ordering more...

FLUX Undies are your complete replacement for pads and tampons and can be worn alone for up to 12 hours.

Our unique built-in tech is moisture wicking, absorbent, and leak-proof, keeping you covered day 'n' night. 

Bikini offers full coverage with no bulk, and the soft lace waistband keeps you comfy in style.

- Wear all night, or for up to 12 hours during the day
- Holds 20-25ml, or four tampons' worth 
- Use FLUX for periods, leaks, post-partum, & incontinence!
- Wear them to school, work, exercise, or simply just to feel comfy on lazy days. 

Find out more on how our undies work.

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