Find Your Perfect Base Layer.
Discover NowGreat Product
"Very comfortable for exercise and daily use. I will be purchasing more!"
Shipping in 3-5 business days
Free shipping on orders over $99
$31.49
$44.99
This item's price has been updated recently to ensure you get the best value.
Dernier prix $44.99 -
-30% Off
Enter your email to receive a notification when this product becomes available.
$31.49
$44.99
This item's price has been updated recently to ensure you get the best value.
Dernier prix $44.99 -
-30% Off
Soft and simple underwear that offers minimalist comfort, the Merino 150 Siren Thong features our Merino Corespun fabric that’s naturally odour-resistant and soft next to your skin.
Good for:

83% Merino Wool, 12% Polyamide, 5% Elastane; Exclusive of Elastic
Machine wash warm. Wash inside out with like colors. Do not use softeners. Fasten all closures to wash and dry. Do not bleach. Do not tumble dry. Line dry in shade. Warm iron. Do not iron print, trims and accessories. Do not dry clean.
Model measurements
Height: 179cm / 5'10". Waist: 62cm / 24". Anya is wearing size S.
Key product measurements
23.9cm (front rise, based on size S); 33.5cm (waist width, size S)
Regular Fit
Slim
Join nature.rewards, icebreaker’s loyalty program.
Unlock thoughtful gifts, free delivery, and members-only discounts all year long.
Merino wool neutralizes unpleasant odors by absorbing odour molecules into its fibers, making them less detectable by the human nose.
Merino fibers efficiently manage moisture, absorbing it from your skin and releasing it into the atmosphere. It can absorb up to 35% of its weight in water without feeling wet.
icebreaker merino wool garments undergo special anti-shrinkage treatment, helping to resist deformation and pilling.
The thermo-regulation properties of merino wool adapt to your body and external conditions, so you can stay warm in the cold and cool in the heat.
Overall rating: 4.766234 / 5 from 308 reviews.
Customers appreciate the Women’s Merino 150 Siren Thong for its perfect fit, flattering color, and breathable design. The fabric is soft and comfortable, though some find the gusset size less than ideal. Overall, the quality and comfort are highly praised.
Review topics: ["fit","size","weather","problem","quality","fabric","material","pants","looks","wear","design","colour","feel","comfort","band","packs","medium","moisture","speed","underwear","waist","texture","style","thong","buy","tags","pair","wool","cut","liners"].
"Very comfortable for exercise and daily use. I will be purchasing more!"
— Becca (5/5)
"These are perfect. I use these for running and skiing, the cut is excellent and the merino obviously helps with all day sports comfort."
— Angela (5/5)
"I now have 5 pair of these - my absolute favorite. Soft comfortable merino fabric against your skin that breathes, flat smooth waistband that doesn't show through yoga pants, and perfect fitting. TTS"
— Marla B. (5/5)
"Love these! I always wait for a sale because they're pricey but this is my fourth pair over the last 2-3 years and they're all still going strong."
— Lauren M. (5/5)
"Great thong that doesn't dig in"
— Olga G. (5/5)
"I've tried a different brand of merino underwear and this one was much more comfortable. Thin, breathable, with a higher percentage of merino. I'm usually an XS but purchased a small based on reviews. It fits well, but I'm wondering if I could have tried an XS. Either way, I love it! Would love to see boy shorts in the beige colour also. I agree that the gusset could be longer."
— AK (4/5)
"I brought a couple pairs of these into the backcountry for nearly two weeks, they were insanely comfortable during strenuous hiking and a quick rinse refreshed them so I could wear again, and they continued to smell and feel fresh the whole trip!"
— Jen (5/5)
"I'm a yoga teacher and I move a lot. This thong makes me forget I'm wearing underwear. Ha! That's a good thing. I love that it's merino. The band is good, it lays flat, and doesn't pinch. There is no scratchy tag! Thank you!! The thong is not itchy and it doesn't slip, slide, or bunch. It washes easily in the sink or washer on cold and dries within a day on a dryer rack. Next to going commando, these are the next best thing. Expensive? Yes. And they are truly worth it. Icebreaker is the best. But I've already bought 3. One more and I'll be able to rotate throughout the week with no problem."
— Commando J. (5/5)
"I originally purchased 3 black for rowing, and came back years later to buy more in nude to wear with white linen pants and other more transparent bottoms. Very happy with the cut and quality of the old pairs and hope the new are the same. For reference I am 5'-5"", 130-135 lbs, 40"" hips and 30"" waist, athletic/curvy build."
— Chris (5/5)
"Despite the price tag on such a small bit of material, these are so comfy that I will continue to buy these! Will last a long time if hung to dry and washed on gentle and even longer if you hand wash"
— LaVa (5/5)
Find the size that fits you best based on people just like you.

Use the chart below to determine your size. If you’re between two sizes, order the smaller size for a tighter fit or the larger size for a looser fit. If your measurements for chest and waist correspond to two different sizes, order the size indicated by your chest measurement for tops and your hip measurement for pants.
Sizing charts:
| XS | S | M | L | XL | |
|---|---|---|---|---|---|
| Waist | 24-26 | 26-28 | 28-30.5 | 30.5-33 | 33-36 |
| Hip | 33.5-35.5 | 35.5-38 | 38-40 | 40-42.5 | 42.5-45 |
| XS | S | M | L | XL | |
|---|---|---|---|---|---|
| Waist | 61-66 | 66-71 | 71-77 | 77-84 | 84-91 |
| Hip | 84-90 | 90-96 | 96-102 | 102-108 | 108-114 |
*Looking for the inseam length? Please refer to the product page to find out.
Our three different fits - slim, regular, and relaxed - ensure that when worn together, layers move and breathe like a single garment.



Your cart is empty

YOUR NEXT ORDER.
Sign up for the icebreaker newsletter and be among the first to hear about new products, exclusive offers, and more reasons to "move to natural."
Check your inbox for an email from us containing your 10% off promotional code.
Success! 🎉 You've successfully signed up for our email list. Stay tuned for exclusive offers, updates, and more!
You are already set to receive the latest offers and news.