Home/Scarlet Period | Made for a Heavy Flow/First Flow Kit
Scarlet Period The First Flow Kit
Scarlet Period Boyshort – PFAS-free, Heavy overnight absorbency, Organic Cotton
Scarlet Period Boyshort – PFAS-free, Heavy overnight absorbency, Organic Cotton
Scarlet Period The First Flow Kit, includes 2 Boyshort
Scarlet Period Bikini Brief - Available in Light & Moderate
Scarlet Period Bikini Brief - Available in Light & Moderate
Scarlet Period The First Flow Kit includes 4 x Bikini Briefs
Scarlet Period The First Flow Kit
Scarlet Period Boyshort – PFAS-free, Heavy overnight absorbency, Organic Cotton
Scarlet Period Boyshort – PFAS-free, Heavy overnight absorbency, Organic Cotton
Scarlet Period The First Flow Kit, includes 2 Boyshort
Scarlet Period Bikini Brief - Available in Light & Moderate
Scarlet Period Bikini Brief - Available in Light & Moderate
Scarlet Period The First Flow Kit includes 4 x Bikini Briefs

First Flow Kit

Mix and match for your flow.

$128.00 $148.00

New to periods, or new to reusables? The leak-free basics to start with confidence. Everything you need, nothing you don't.

    Comfy & Body-safe
    Save $$ with Sets
    Fast-absorbing
    Machine Washable
Scarlet Period Bikini Brief (Size)
Scarlet Period Bikini Brief (Style)
Scarlet Period Boyshort (Size)

✨ Complete Cycle Coverage: Pick from Light-Moderate and Moderate-Heavy absorbency.

✨ Ultra-Soft & Breathable: Made from GOTS Certified Organic Cotton for all-day comfort.

✨ Leak-Proof Technology: Absorbent gusset locks in moisture to keep you dry and fresh.

✨ Sustainable Swap: A zero-waste alternative that’s better for the planet and your body.

✨ Versatile Selection: Pack includes 4 x Bikini Briefs (Light or Moderate) and 2 x Boyshort (for extra coverage on heavy nights).

✨ Rinse in Cold Water: To keep them fresh, rinse in cold water until the water runs clear after wearing them.

✨ Machine Wash Cold: Toss them in with mild detergent (no bleach or fabric softener, please).

✨ Dry with Ease: Line dry or tumble on low - no need for extra care.

✨ Need more info? Please read our complete guide to caring for your period underwear here.

✨ 95% GOTS Certified Organic Cotton – soft, breathable, and sustainably grown.

✨ 5% Spandex – for the perfect amount of stretch.

✨ Quick-Dry Gusset – made from Polyester/PUL to wick away moisture and prevent leaks.

✨ PFAS-Free & Toxin-Free – no harmful chemicals, just pure comfort.

✨ Fit Note: We run slightly smaller - if you're between sizes, size up.

✨ Teen-to-Adult Fit: Our sizing is unique - please refer to both the numerical (e.g. 10, 12) and letter sizing (e.g. M, L) in our guide.

✨ Australian Sizing: We use AU sizes - international customers, check our Size Guide.

✨ Still Unsure? Contact us for advice. We love a chat!

Did you know that over 12 billion pads and 7 billion tampons end up in landfills yearly? By choosing Scarlet, you're supporting a more sustainable future where self-care and sustainability go hand in hand.

✨ GOTS Organic Cotton: Soft, breathable, and sustainably grown.

✨ PFAS-Free, No Harmful Chemicals: Because your body - and the Earth - deserve better.

✨ Eco-Conscious Manufacturing: Crafted with care to reduce environmental impact.

✨ Recyclable Packaging: Minimal waste for a cleaner world.

Scarlet is proud to be a 1% for the Planet member, joining a global movement dedicated to environmental conservation.

Size Chart

Size chart for First Flow Kit
Scarlet Period The First Flow Kit

First Flow Kit

$128.00 $148.00
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Your period starter pack

Say hi to the First Kit: everything you need to kick things off with comfort, confidence, and zero plastic shame.

This three-piece set covers you from class to sleepovers - soft, leak-proof, and designed to last.

  • 4 x Bikini Briefs for everyday flow
  • 2 x Boyshort for overnight or heavier days
  • Washable, reusable, and kinder on the planet
  • Chemical treatment-free, including PFAS
BUY NOW

Your Questions, Answered

How do they work?

Scarlet Period Underwear is designed to fit like normal underwear and features multi-layered leak-proof technology that wicks away moisture, absorbs fluid, and contains it to keep you dry and protected. 

The built-in leak-proof technology is harder working than disposable pads which means it can safely hold more liquid and last for years not hours. Loved by all; you can read some reviews.

Do I need to wear a cup, tampon, or pad too?

Depending on the absorbency you choose and the heaviness of your flow, you can wear our period undies on their own or as backup along with a Period Cup or tampon.

What does the absorbency level mean?

Super Light: Holds up to 1 teaspoon, equal to less than one regular tampon. Think of it as a new-age panty liner, great for spotting, light leaks and discharge. Try: Invisible Thong

Light: Holds up to 3 teaspoons, equal to 2 regular tampons or one pad. For light days, drips and discharge. Try: G-String or Bikini Brief in Light-Moderate

Moderate: Holds up to 5 teaspoons, equal to 3 regular tampons or 2 pads. For moderate days, or as extra defence on heavy days with our Period Cup. Try: High-Waist Brief or Bikini Brief in Moderate-Heavy

Heavy: Holds up to 7 teaspoons, equal to 4 regular tampons or 3 pads. Our heavy hitters are great worn on their own, day or night. Try: Boyshort or Period Cup

How do I wash them?

After use, rinse them in cold water (we recommend in the shower) until they run clear. Then, machine wash in cold water with mild detergent (no bleach!). Try our Laundry Bag to safeguard them on laundry day. Then just hang out to dry (the sunnier the better) or tumble dry on low - that’s it!

TIP: If it’s your first wear, pop them in the washing machine with your next cold cycle - washing them before wearing activates their absorbency even more.

How do I pick the right size for me?

We get it, sizing for bottoms is anything but standardised. Which is why this size guide will help break it down for you. Make sure to check both our numeric and letter sizing so no confusion (ie. our large is a 12).

When in doubt, feedback tells us better to size up. Still confused? You can also email us for help at support@scarletperiod.com.

Why buy a bundle?

Save money and stay prepared! With your period lasting between 3-8 days, a multipack ensures you have enough pairs to manage your cycle comfortably. Check out some of our best-selling sets.
★★★★★

"The organic cotton is super soft, and I feel super secure to wear these even on heavy days. Highly recommend!"

NEWS

★★★★★

"The Boyshort gives you more coverage for those days you feel a bit more vulnerable to leakage or overnight."

Body and Soul

★★★★★

"I was walking, catching up with friends and going to Pilates. All without a leakage scare in sight."

Beauty Heaven

Real advice for real cycle days