Excellent product, fits true to size.
Bought these for my daughter, she loves them. Keeps her comfortable and prevents any leaks on her heaviest nights.
Great service and great product.
How to make your daughter's first period EASY and FUN!CLICK HERE TO READ.
Welcome to Knicked, Welcome to Puberty and Periods SHOP HERE
Terms & Policies
Please see each product page, for individual sizing.
As a general rule, please choose the same size for our period undies and period swimwear as your child's regular underwear size.
Our period underwear is designed here using Australian Child/Youth underwear guidelines. It's important to note that child sizing, also crosses over into women's sizing at our 12/14, so we have also shown this on our sizing charts (on each individual product page) to assist.
We also understand purchasing online can make judging sizing difficult and everyone has a different body shape (literally hundreds of waist & hip combinations) so we have created guides on each product page to help you choose the best fit for each product, or feel free to email our helpful team at theteam@knicked.com.au with waist & hip measurements so we can assist further.
To measure against existing underwear: use the flat lay measurement (side seam to side seam on the waistband) to compare with their current underwear.
Don't panic if you do find you've ordered the wrong size, KNICKED will happily exchange sizing and also cover the postal costs to reship (once per order) as long as underwear has been tried on over clean underwear and returned in AS NEW condition (not washed/worn free of lint/hair/marks), and packaging in original condition.
Please click here for our Exchange/Refund Forms & Guidelines to organise an exchange.
Knicked BFFs™ - Bestie Flow Friend
The World's First 2-in-1 Hybrid Period Undies
Swimming? Dancing? Unexpected period? School day?
We've got you covered.
Our Knicked BFFs™ are the ultimate SOS period solution - the world's first 2-in-1 hybrid period undies that work both in AND out of water. Wear them under your bikini, leotard, leggings, or even regular underwear for total leak-proof confidence anywhere, anytime.
💖 What Makes Them Different?
Unlike regular period underwear OR period swimwear, our BFFs feature:
✔ 2-in-1 hybrid design - works in water AND out of water
✔ Waterproof technology that blocks water from getting in
✔ Leak-proof protection that locks period flow from getting out
✔ High-cut, discreet design under any outfit
✔ Award-winning stop-leak technology
✔ Soft, slimline & seriously clever
✔ Compliant with Swimming Australia's Inclusive Swimwear Policy
That means one pair replaces period swimwear, dance undies AND heavy flow underwear - saving you over $80 and endless outfit changes.
🩰🏝️ Perfect For:
• Under swimwear at the pool or beach
• Under leotards for dance & gymnastics
• Under leggings, shorts & everyday clothes
• Emergency period protection at school
• Sleepovers & school camps
• Any activity where you need total confidence
🌿 The Ultimate Schoolbag Essential
Created by a mum, designed for real teen life.
Our BFFs are:
• Ultra discreet & comfortable
• Reusable & sustainable
• Budget-friendly (replaces 3+ products)
• Made to move with you
• Comes with a waterproof, odour-proof wet bag
Because periods shouldn't mean missing out on swimming, dancing, or living your best life.
Knicked period undies have always been and will continue to be FREE FROM NASTIES such as PUL'S (plastics) or PFAS (chemicals).

How to wear:
These aren't your average undies - pull them on, then up high at the sides so they sit snugly and low under the belly for the best protection.
Care tip:
Wash before first use. Each pair comes in a reusable, waterproof, and odour-proof wet bag – perfect for storing your BFFs in your bag or when they're wet, waiting for a wash. Less waste, more wow.

Our teen models are wearing a Teen 12/14 (adult 6 or 8).
Please use the flatlay measurements to compare to another brand or existing pair to select the correct fit and if between sizes or very tall we recommend sizing up.
Tracked postage is $9.95
Express postage is $14.50
Orders over $99 receive complimentary FREE REGULAR SHIPPING
Knicked will exchange item(s) that have not been washed, worn and are in AS NEW condition, we request you submit our Exchange Form within 14 days of receiving your product. Knicked will cover one new shipping cost as a gift to assist - please note: if purchased on sale or outside Australia item(s) can ONLY be returned for a gift voucher to repurchase a new size or style within 5yrs.
Excellent product, fits true to size.
Bought these for my daughter, she loves them. Keeps her comfortable and prevents any leaks on her heaviest nights.
Great service and great product.