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Discreet protection, this Thong means you can still wear white
Invisible, invincible: embrace discreet protection!
Invisible feels as good as it looks.
Perfect for no lines
Nude for discreet period protection
Great for discharge, sweat and spotting, make pantyliners a thing of the past.
Light Flow, Big Comfort: Scarlet Invisible G-String
Like a panty liner, but make it stylish! Shown in black
Like a panty liner, but make it stylish. Shown in nude
Find your best Invisible Thong size
Check Invisible Thong Absorbency

Scarlet Period Invisible Thong

Super Light

eqv. 2 tampons

This barely-there thong stretches to your every move. Discreet and comfortable, perfect for light flow and spotting days.

  • Fast-absorbing
  • Leak-proof
  • Comfy & Body safe
    Comfy & Body safe
  • Machine washable
    Machine washable
  • Odour-free
    Odour free
  • Stylish & Discreet
    Stylish & Discreet
Upgrade your order
Keep your undies safe with a Scarlet Period Laundry Bag +$10
Item will be included
Shop now to try risk-free for 30 days

We promise you'll love them or we'll give your money back!


The Scarlet Period Invisible Thong is your go-to period underwear for discreet spotting protection. The buttery soft fabric with 360° stretch will ensure you feel sexy, even on days when you bleed. Available in black or nude.

With its quick drying thin and absorbent gusset, it absorbs 1 teaspoons of fluid (along with sweat and moisture!) like a panty liner, so you can look great and feel confident every day. It’s the perfect everyday underwear for light leaks and discharge, even when you’re not on your period.

The Sultry Days Set
Super Light

Machine washable and reusable, they’re an eco-friendly and cost-effective alternative to disposable pads and tampons. 

After use, rinse in cold water until it runs clear. Machine wash cold with mild detergent, do not use bleach or fabric softener. Line dry or tumble dry on low.


76% Polyamide, 24% Elastane, and a Polyester Quick Dry Gusset. Free from added chemical treatments, including PFAS (independently lab tested).


Harder working than disposable pads and tampons, our Period Underwear lasts for years not hours. 

Did you know more than 12 *billion* pads and 7 *billion* tampons are thrown out every year. The average person with a period uses 11,000 pads, tampons and panty liners in their lifetime. By switching to Scarlet, you're supporting a period and planet positive future.

Scarlet is a proud member of 1% for the Planet, joining a global community of brands and individuals giving back to the environment.


If you were looking for a sign to break up with panty liners, this is it.

You can still feel sexy on your period. Our discreet Invisible Thong proves it.

Designed in a barely-there style with light absorbency, it's perfect for light flows and spotting days. Made with a buttery soft, 360° stretch fabric, it feels like you're wearing nothing at all.

Like wearing nothing at all
Buttery soft fabric with 360° stretch
Chemical treatment-free, including PFAS
Like a new age panty liner, catches sweat and drips
Absorbs the equivalent of 1 teaspoons of fluid

Your questions, answered


Scarlet Period Underwear is designed to fit like normal underwear, and feature a multi-layered leak-proof technology that wicks away moisture, absorbs and contains fluid 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.


When it comes to our periods, every flow is different. Heck, every day is different. Which is why we have a range of absorbency levels to suit. Use this as a guide to get the right fit for your flow, so you'll never stress about leaking on the train again.

Super Light: Holds up to 1 teaspoon, which is just a bit less than 1 regular tampon. Think of it as a new-age panty liner, so it’s great for spotting as well as light leaks and discharge. Try: Invisible Thong

Light: Holds up to 3 teaspoons, which is equal to 2 regular tampons or 1 pad. This is for light days to save you from pesky drips, discharge, and lighter flows. Try: G-String, Bikini Brief in Light or Swim range

Moderate: Holds up to 5 teaspoons, which is equal to 3 regular tampons or 2 pads. Go for this on your moderate dates, or as extra defence on heavy days with our Period Cup. Try: High-Waisted Brief or Bikini Brief in Moderate

Heavy: Holds up to 7 teaspoons, which is around 4 regular tampons or 3 pads. It’s our heavy hitter, making them great for full flow days and overnight. Try: Boyshort or Period Cup


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

On heavy days, we recommend travelling with a water-resistant travel bag such as the Toiletry Bag, along with a spare pair, so you can change them if needed, pop them straight away and rinse (if you CBF) when you get home.

And if you are feeling Cup curious, you can click to learn more about how Period Cups work. They’re really not as scary as you think!


Nope – who’s that organised? That’s why our Laundry Bag is ace – simply throw your used pair into the bag and store for when you have a full load. Some people like to give them a quick rinse in the shower before popping into the bag, and others don’t. It won’t affect the lifespan of your underwear.

Once you are ready, simply toss them in on a cold wash cycle with mild detergent (no bleach!). DW, your other clothes will be just fine! For drying, you have two options: tumble dry on low or hang them out to dry in the sun. 

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.

Click to read more about how Period Underwear works


This is a new way to period, and we understand fit may take a couple of goes to get into the swing of things. So, we have a 30-day risk-free trial to support you to find the perfect pair. Basically, if it’s your first time shopping with us and you’re not happy with your product, you may be eligible to claim a refund on that product, even if it’s used. Just email us at


We get it — sizing for bottoms is anything but standardised. Which is why this size guide will help break it down for you. For extra ass-urance, make sure to whip out your trusty measuring tape. (Most likely stashed at the bottom of your junk drawer.) 

Make sure to check both our numeric or letter sizing so no confusion (ie. Our large is a 12). And when in doubt, we advise to size up.

Still confused? Click for more information on our Returns Policy and our 30-Day Trial Policy. You can also email us at

"I can wear during ovulation when I get those annoying leaks or sneeze too hard! I loaded up on these and got a couple of weeks’ worth, that’s how much I love these!"

Melissa M.

"I love the seam-free for wearing out and about."

Sophie H.

"After trying other scarlet undies I thought I'd give these a go. So happy I did. These too are awesome."

Kate S.

"I love that I can wear these panties for light leaks and discharge, even when I'm not on my period."

Cassie H.

"The most comfortable thong. These are super soft, stretchy and impressively unnoticeable. Have been wearing on first and last days of my period, when it’s lighter, and they were perfect!"

Jasmine G.

"I wear them every day, even when I'm not on my period because they're really comfortable."

Kristie N.

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