KNOW YOUR FLOW
Absorbency Guide
Our FlowBase™ – Waterproof Swim Underwear for Periods have a Moderate absorbency.
Check out the below guide to see how this level stacks up against our other products.
FlowBase™ – Waterproof Swim Underwear for Periods
●●○○○ | Moderate - Check out our absorbency guide here
60 Day Risk Free Trial
Swim, float, dive, or lounge—FlowBase™ is your discreet, absorbent swim-safe underwear made to wear under your regular swimmers. Designed especially for teens, FlowBase™ is as comfy as your fave undies, only water-ready.
Perfect for school swimming, squad training, or any time they’re required to wear their usual bathers. With a high-leg cut and flat, seamless design, FlowBase™ sits smooth against the skin for a no-show effect under most styles.
This game-changing layer gives teens the freedom to move, splash, and swim as usual—even on period days.
🤓 The Techy Stuff:
Made with a water-resistant outer coating to keep water out and advanced absorbent layers to hold your flow in, FlowBase™ gives you the comfort and freedom to enjoy every splash without second-guessing.
✨ Invisible Under Swimwear:
Thanks to its seamless edges and high-leg cut, it stays hidden under most swim styles with full or regular coverage.
🩸 Discreet but Mighty:
Holds up to the equivalent of 2–3 tampons or 4 regular pads, all without the bulk.
🌊 Made for Movement:
Wear it under a bikini or one-piece, or on its own during lighter days, spotting, or for peace of mind during cycle shifts.
Why You’ll Love FlowBase™:
⭐ Water-Resistant Coating
Prevents pool or ocean water from soaking in, while locking your flow in safely.
⭐ Invisible Under Swimwear
No seams, no bunching, no awkward lines—just smooth support where it matters.
⭐ Same As 4 Pads
High-performance absorbency with zero visible bulk.
⭐ Made to Last
Chlorine-resistant and durable—just give them a rinse after use and they’re ready for next time.
⭐ OEKO-TEX® Certified
No nasties, no harsh chemicals—just gentle, body-safe comfort.
⭐ Swimming AUS Compliant
Tested against Swimming Australia's Inclusive Swimwear Policy, so you can wear them with confidence.
How to Wear:
Slip them on under your swimmers like you would any undies. Perfect for:
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Beach or pool days during light flow or spotting
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Teens building confidence with cycle care
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Those who prefer layered protection
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Post-swim freshness or backup comfort
What's to love about our FlowBase™ – Waterproof Swim Underwear for Periods?
When your undies arrive, try them on over your regular, clean underwear before use to check the fit. Make sure to give them a wash before your first wear to improve the absorption performance.
Then to use the undies, simply wear them like you would with any of your other underwear.
How long you wear your underwear for will come down to personal preference and your flow. We recommend changing every 6-12 hours.
Washing period undies and period bikinis/ swimwear is simple and hassle-free.
They can be machine-washed (we recommend using a garment bag, cold water and liquid natural detergent), and then line-dried for best results.
We do recommend rinsing them well prior to popping them in the machine, however this isn't necessary.
Think your individual decisions won't make a difference?
Well, did you know more than 12 BILLION pads and tampons are thrown out every year worldwide? Let's break this down even further to see the impact you CAN make - the average woman alone uses 11,000 pads, tampons and panty liners in their lifetime. That’s a lot of landfill! It's time to make the switch to Eco Period, you won't look back.
IS IT YOUR FIRST TIME TRYING REUSABLE PERIOD CARE?
Once you start, you'll never go back to traditional single-use period care products again!
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Eco Period Australia underwear absorb your period.
Every pair is made with our signature technology that's odor-controlling, super-absorbent, and leak-resistant. This 4 layer technology works together to do it’s thing (aka keep you fresh and dry). Take a look at our How It Works page to learn more.
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Yes, our period underwear has been designed to be worn alone, with no tampons or pads required. If you wish to wear a menstrual eco cup as well, this can extend the wear time of your eco briefs.
Also the length of time you can wear each pair depends on your flow.
As a general rule, we recommend choosing heavy or super absorbency for your heavy flow days and moderate or light for your lighter days.
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This comes down to personal preference and your flow, however you can wear a pair of undies for as long as 24 hours. We find most of our customers like to change every 8-16 hours. There's no right or wrong here!
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Our range of period underwear range from Super > Light. Scroll down to check out our Absorbency Guide here to decide which level is right for you.
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Firstly, work out how many days of your cycle are heavy and moderate/light. Then, you can calculate the number of briefs you will need using this guide:
Heavy flow days:
- Within a 24 hour period, we'd recommend changing 2-3 times.
- Suggested change times - morning, midday (optional if your flow is heavy) and at the end of the day.
Moderate/light flow days:
- Within a 24 hour period, we'd recommend changing 1-2 times.
- Suggested change times - morning and at the end of the day.
So you can allow ample time for washing + drying, we suggest buying double the amount you calculate above, so you're never caught out without a clean pair to wear!
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If you use period cups or pads you might not need as many pairs of period underwear.
Browse our collection of eco-pads and menstrual cups to grow your eco-friendly period solutions.
If you're often on the move and wish to change your underwear, we recommend getting a wetbag for your used underwear to store them before you're able to wash them.
WHO WE ARE
Eco Period offers beautifully crafted, quality period garments that are made to last, and are just as good for your body as they are for the environment.
We are passionate about making a difference through our products and hope to help you transition (or continue) your journey towards zero waste, eco and organic period solutions.
The textile industry has historically been associated with environmentally harmful processing, animal welfare issues, and complex social compliance issues such as child labor, workers’ wages, benefits, fast fashion and health and safety. The demand for certified, sustainable products is growing rapidly.
Organic cotton is cotton grown without any chemical fertilizers or pesticides which is better for human health as well as nature.
Organic cotton is different from conventional cotton in many respects, and the difference starts at the fibre stage.
All cotton in our products is organically cultivated and comes from suppliers who are inspected and certified as part of the Control Union Certification program. This organization has established criteria for organic production according two certification programmes, GOTS or Organic Exchange Certification. Read more about Control Union here.
Eco Period works with manufacturers that use Control Union Certified certified organic, recycled and sustainable materials.
Many of Eco Period Australia's products are certified according to OEKO-TEX® Standard 100. OEKO-TEX® Standard 100 is an independent testing and certification system for textile products at all stages of production. OEKO-TEX® covers the production processes itself and includes the finishing. It certifies all types of fabrics but also includes thread, press buttons, elastics, labels etc. We believe it is important to consider every environmental aspect and we are constantly looking for ways to reduce our environmental impact. Fabrics and articles OEKO-TEX Certificates: SHKO 068780 / BEAO 088186 /SH015175169