UltraThin Bikini: Holiday 3-Pack

Get your teen ready for the holidays and every period that comes with it.

These period undies protect against period leaks, sweat, and discharge. A classic silhouette made from soft, stretchy, quick-drying fabric with a thin liner that absorbs the same as about 1 regular tampon. Wear them as everyday underwear, as full protection on light days, or backup on heavy days.

Key Features:

- Quick-Drying

- Moisture and Sweat Wicking

- Absorbs the same as about 1 regular pantyliner/tampon

- Super soft & stretchy

- Invisible under leggings or shorts (aka no visible seam lines)

- Patented leakproof technology

more absorbent protection, without any extra bulk
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Each pair holds about 2.5 super tampons' worth of blood.
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Rapidly absorbs moisture to keep you fresh and dry all day.
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Allows air to circulate to keep you cool and dry.
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Simply care with mild detergent and machine wash on cold.
Get your teen ready for the holidays and every period that comes with it.

These period undies protect against period leaks, sweat, and discharge. A classic silhouette made from soft, stretchy, quick-drying fabric with a thin liner that absorbs the same as about 1 regular tampon. Wear them as everyday underwear, as full protection on light days, or backup on heavy days.

Key Features:

- Quick-Drying

- Moisture and Sweat Wicking

- Absorbs the same as about 1 regular pantyliner/tampon

- Super soft & stretchy

- Invisible under leggings or shorts (aka no visible seam lines)

- Patented leakproof technology

Machine wash cold, do not bleach, do not iron, do not dry clean, lay flat to dry.

Body: 77% Nylon, 23% LYCRA® XTRA LIFE™Spandex;

Fresh Fix Technology®Gusset: Gusset 1: 86% Cotton, 10% Spandex, 4% Carbon; Gusset 2: 96% Polyester, 4% Spandex; Gusset 3: 83% Polyester, 11% Spandex, 6% Polyurethane


Additional Product Ingredient Information

For items with a 20% or more discount, you may exchange for another item or return for store credit. No refunds can be accommodated. 

Items marked as “Flash Sale” or “Clearance” are final sale, meaning no returns, exchanges or refunds can be accommodated. No exceptions. 

Please note: Sale items are not eligible for our First Pair Risk-Free Policy.


We offer free standard shipping on all orders over $70. We ship our items via DHL or Canada Post depending on your location. Please allow 1-2 business days for your items to be processed and shipped. During high volume periods, your order may take up to 7 business days to dispatch from our warehouse location.

US Orders: Please allow 3–10 business days for orders to arrive. 

International Orders: Please allow 10–25 business days for orders to arrive.  

NOTE: Orders placed on Friday after 1 PM will not be processed until the following Monday.   

CANADIAN CUSTOMERS: Shop www.knixteen.ca to order in Canadian currency.

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FOR THIS GENERATION
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FOR THE PLANET
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FOR THIS GENERATION
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FOR THE PLANET
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nothing is tmi here—we promise.
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Heavy Absorbency

Absorbs about the same as 3 super tampons. Perfect for overnight protection or your teens heaviest days when changing into a fresh pair might not be convenient.


Moderate Absorbency

Absorbs about 2.5 super tampons' worth of blood. Ideal for medium period days, discharge and sweat.


Light Absorbency

Absorbs about the same as about 1 regular tampon worth of blood, sweat or discharge. Ideal for lightest period days, spotting, sweat and discharge.

Each pair has a built-in liner that absorbs period blood. Kt Period Underwear is categorized by light, moderate and heavy flows so you can find the right pair for your teen’s needs.

All of our period underwear, swimwear, reusable pads, and activewear have our patented leakproof technology built right in. Liner’s are discreet and comfortable, and fit for your teen’s unique flow. 

That’s up to your teen or tween! Every flow and comfort level is different.

Depending on the absorbency level of the period underwear and the heaviness of your teen’s flow, they can wear our period undies on their own or as a backup to tampons or menstrual cups. 

We always recommend they choose an option that makes them feel most confident!

Step 1: Give your teens underwear a quick rinse under cold water.

Step 2: Throw it in the washing machine with your regular clothes. Wash on cold with mild detergent (no softener or bleach).

Step 3: There are two ways to dry them depending on the undies you have: lay flat to dry for medium absorbency products, or tumble dry on low for high to super absorbency products.

Step 4: That’s it! No ironing needed.

Check out our size chart here. If you want some help, we have virtual fitters ready on deck to help your teen find their perfect fit. Book a video call with them today.

Because they’re, well, underwear, we can’t accept exchanges or returns on used items. BUT your teen can try their first pair on your first order risk-free for 30 days!

If you ordered the wrong size of period underwear, we’ll send you a different pair at no cost or offer you a standard refund within 30 days of delivery (excluding original shipping fees).

If your order included multiple period underwear, open, wash, and wear one pair only. That way if you don’t love them, any unopened packages from the same purchase will be eligible for an exchange or standard refund (excluding original shipping fees).

All unopened packages will be donated to local organizations to support people in need.

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Sustainable
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Absorbent
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Comfortable
Image of a chrome heart surrounding text
Sustainable
Image of a chrome heart surrounding text
Absorbent
Image of a chrome heart surrounding text
Comfortable
Image of a chrome heart surrounding text
Sustainable
Image of a chrome heart surrounding text
Absorbent
Image of a chrome heart surrounding text
Comfortable
Image of a chrome heart surrounding text
Sustainable
Image of a chrome heart surrounding text
Absorbent
Image of a chrome heart surrounding text
Comfortable
Image of a chrome heart surrounding text
Sustainable
Image of a chrome heart surrounding text
Absorbent
Image of a chrome heart surrounding text
Comfortable
Image of a chrome heart surrounding text
Sustainable
Image of a chrome heart surrounding text
Absorbent
Image of a chrome heart surrounding text
Comfortable
Image of a chrome heart surrounding text
Sustainable
Image of a chrome heart surrounding text
Absorbent
Image of a chrome heart surrounding text
Comfortable
Image of a chrome heart surrounding text
Sustainable
Image of a chrome heart surrounding text
Absorbent
Image of a chrome heart surrounding text
Comfortable
Image of a chrome heart surrounding text
Sustainable
Image of a chrome heart surrounding text
Absorbent
Image of a chrome heart surrounding text
Comfortable
Image of a chrome heart surrounding text
Sustainable
Image of a chrome heart surrounding text
Absorbent
Image of a chrome heart surrounding text
Comfortable
Image of a chrome heart surrounding text
Sustainable
Image of a chrome heart surrounding text
Absorbent
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100% of reviewers would recommend this product to a friend
Comfort
Rated 5 out of 5
Effectiveness
Rated 5 out of 5
Fit
Rated 1 on a scale of minus 2 to 2, where minus 2 is Runs Small, 0 is True to Size and 2 is Runs Large
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Reviewed by sarah F.
Verified Buyer
Rated 5 out of 5

Great

Bought knix teen period underwear for my daughter. Had the wrong size but was able to exchange easily for a size that fits her. She says they are comfortable.

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Comfort
Rated 5 out of 5
Fit
Rated 1 on a scale of minus 2 to 2, where minus 2 is Runs Small, 0 is True to Size and 2 is Runs Large
Effectiveness
Rated 5 out of 5
Ease of Use
Rated 5 out of 5
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