Lace Brief Period Underwear
- Paranoid about your period leaking? Our all-day leakproof protection holds for hours so you can actually get on with your day.
- Sick of that bulky pad feeling? Our ultra-thin design stays invisible under any outfit, you'll forget you're even wearing it.
- Period bloat making everything uncomfortable? Our soft stretch fabric moves with your body, no waistband digging in even on your heaviest days.
SIREN Periodwear Sizing Guide

Measure Your Waist
Where: Wrap the tape around the narrowest part of your waist — above your belly button and below your ribs.
Tip: Keep it snug but comfortable; you should be able to breathe easily.
Measure Your Hips
Where: Stand with your feet together and measure around the fullest part of your hips and buttocks (usually 7–9 inches below your waist).
Tip: Make sure the tape is level all the way around for an accurate measurement.
Consider Stretch & Fit
✔ SIREN’s fabrics are sculpting and high-stretch for a flattering fit.
✔ For our Super Absorbency and Lace Brief, size up if you’re between sizes (these styles have less stretch due to their absorbent layers).
✔ For our Seamless cheeky styles, choose your regular size or size down for a firmer feel.
💌 Need a Hand?
Not sure which size to choose?
Message us and our team will help you find your perfect fit so you can feel confident, comfortable and completely covered.
Heavy flow days shouldn't mean wearing something that feels like a nappy. Full coverage, zero bulk, all day.
- Holds up to 6 tampons worth - medium to heavy flow handled all day
- Leakproof lining that doesn't quit - dry from morning to night
- Curve-hugging, breathable fabric - supportive without feeling restrictive
- Lace trim finish - feminine, flattering, zero irritation
- No VPL, no bulk, no bunching - completely invisible under clothing
Best for: Medium to heavy flow • All-day wear • When you still want to feel like yourself
Can I wear SIREN instead of pads or tampons?
Yes - SIREN is designed to fully replace them. No doubling up, no backup needed. Just put them on and get on with your day.
How long can I wear them?
Up to 10+ hours depending on your flow. Day or night, they've got you covered.
What's your return policy?
We offer a 60-day money back guarantee - try them risk-free.
- Worn a pair and it's not for you? Contact us within 60 days for a refund. You keep them.
- Multiple items ordered? Any unworn items need to be returned for a full refund.
- Size exchange or change of mind? Items must be unworn and return shipping costs are the customer's responsibility.
Email admin@sirenperiodwear.com with your order number and we'll sort it.
Are the fabrics safe?
Yes. SIREN uses certified, body-safe materials - OEKO-TEX® certified, FDA-approved, and GRS-compliant. No harmful substances, no compromises.
How do I wash them?
- Rinse in cold water after use
- Machine wash cold, gentle cycle
- No bleach, no fabric softener
- Air dry flat - no tumble drying
Cared for properly, they'll last years.
Where do you ship?
Australia-wide 🇦🇺 FREE standard shipping on orders over $100.