Front view of the black Racerback Sports Bra, a seamless Merino wool compression sports bra that wicks sweat on hikes.
Back detail of the black Racerback Sports Bra, a heavyweight, compressive seamless Merino wool knit that's breathable.
Woman with arms raised in the black Racerback Sports Bra, a breathable, moisture-wicking seamless Merino wool sports bra.
Woman in a yoga backbend in the black Racerback Sports Bra, temperature-regulating seamless natural fiber activewear.
Front view of the black Racerback Sports Bra, an odor-resistant seamless Merino wool sports bra that keeps you dry and cool.
Woman stretching in the black Racerback Sports Bra, our most compressive bra in quick-drying seamless 76% Merino wool.
Woman with hands overhead in the black Racerback Sports Bra, an odor-resistant seamless natural fiber compression sports bra.
Woman in camel pose in the black Racerback Sports Bra and leggings, sweat-wicking seamless Merino wool activewear.
Woman by a river in the Natural White Racerback Sports Bra, a moisture-wicking seamless Merino wool bra with pad sleeves.
Woman stretching in the Deep Willow Racerback Sports Bra, a sweat-wicking seamless Merino wool compression sports bra.
Fabric detail of the Deep Willow seamless Racerback Sports Bra, heavyweight 76% ZQ+ Merino wool natural fiber knit.
Back view of the Deep Willow Racerback Sports Bra, a breathable seamless racerback design for a full range of motion.
Front view of the Deep Willow Racerback Sports Bra, a breathable seamless Merino wool sports bra for active women.
Back view of a woman in the Deep Willow Racerback Sports Bra, odor-resistant seamless natural fiber activewear.
Woman in tree pose in the Slate Racerback Sports Bra and Compressive Leggings, breathable seamless Merino wool activewear.

Essential Racerback Sports Bra

$85.00 USD
532 reviews
532 reviews
Merino wool benefits listed with icons: [Sheep icon] Merino wool = Sweat free freshness [Knit icon] Seamless knit = Second skin comfort [Sustainability icon] ZQ Merino = Ethical and sustainable fiber
BRANWYN Merino wool Essential Busty Bra size guide slider.
Color:Black
Size:XS
Quantity:
In stock

Racerback Sports Bra Size Guide

Size guide banner
A/B C D DD F G
<30 XS XS XS XS S S
32 S S S S S/M M
34 S/M S/M M M M M/L
36 M/L M/L M L L L/XL
38 L L L L/XL XL XL
40 XL XL XL XL/XXL XL/XXL XXL
42-44 XXL XXL XXL XXL XXL XXL

Tell me about fit:

UPDATED 5.13.26: Our Essential Racerback Sports Bra is intentionally designed to fit snugly against the body for secure, stay-put support. To find your best fit, start with the band—our sizing is based on field testing where two fingers fit comfortably between the band and your body, but not more.

Because this fabric is more compressive than our Essential Busty Bra & Bralette, women with a fuller bust and smaller ribcage may prefer to size up 1–2 sizes for their ideal balance of support and comfort.

If you prefer a slightly less compressive feel overall, we also recommend sizing up. And if your new bra feels just a touch snug at first, give it a few wears and washes—like most high-performance natural fibers, it will gently relax and mold to your body over time before considering an exchange. Not sure? Please reach out to our Customer Happiness team,

Will it stretch out?

Yes! Performance Innerwear is designed to give a little with wear and washing, molding to your shape while keeping support and comfort.

How to measure your band size:

  • Measure snugly around your rib cage, directly under your bust.

  • Add 3 inches to that measurement.

    • Example: A 31" rib cage + 3 = 34, so your band size is 34.

  • If the result is an odd number, round UP to the next even band size.

    • Example: A 32" rib cage + 3 = 35 → round up to 36.

Racerback Sports Bra Size Guide

Size guide banner
A/B C D DD F G
<30 XS XS XS XS S S
32 S S S S S/M M
34 S/M S/M M M M M/L
36 M/L M/L M L L L/XL
38 L L L L/XL XL XL
40 XL XL XL XL/XXL XL/XXL XXL
42-44 XXL XXL XXL XXL XXL XXL

Tell me about fit:

UPDATED 5.13.26: Our Essential Racerback Sports Bra is intentionally designed to fit snugly against the body for secure, stay-put support. To find your best fit, start with the band—our sizing is based on field testing where two fingers fit comfortably between the band and your body, but not more.

Because this fabric is more compressive than our Essential Busty Bra & Bralette, women with a fuller bust and smaller ribcage may prefer to size up 1–2 sizes for their ideal balance of support and comfort.

If you prefer a slightly less compressive feel overall, we also recommend sizing up. And if your new bra feels just a touch snug at first, give it a few wears and washes—like most high-performance natural fibers, it will gently relax and mold to your body over time before considering an exchange. Not sure? Please reach out to our Customer Happiness team,

Will it stretch out?

Yes! Performance Innerwear is designed to give a little with wear and washing, molding to your shape while keeping support and comfort.

How to measure your band size:

  • Measure snugly around your rib cage, directly under your bust.

  • Add 3 inches to that measurement.

    • Example: A 31" rib cage + 3 = 34, so your band size is 34.

  • If the result is an odd number, round UP to the next even band size.

    • Example: A 32" rib cage + 3 = 35 → round up to 36.

Built for when you push harder:  our seamless Racerback Sports Bra is knit from 76% Merino wool and is heavier and more compressive than our Essential Bralette, Supreme Bra, and Busty Bra. Expect a snug, locked-in fit that hugs your body, with body-mapped contours for added lift and stability.

The integrated straps and racerback design sit squarely on your shoulders and away from your neck, giving you a full range of motion and all-day comfort. It’s a pullover style with sleeves for removable pads (pads not included).

Made for trail runs, single-track laps, boulder projects, and your next HIIT session, it moves with you wherever your day, or your workout, takes you.

Our heavyweight 4-way POWRspun™ knit combines 76% extra-fine 17.5-micron ZQ+™ Merino wool, 14% nylon, and 10% elastane for durability, stretch, and breathability. BPA- and PFAS-free.

  • Our most compressive bra, in a heavier weight than the Essential Bralette, Supreme, and Busty Bras
  • Body-mapped contours for lift
  • Racerback, pullover design for a full range of motion
  • Sleeves for removable pads (pads not included)

Bonus: Our ZQ+ and RWS-certified Merino is also regenerative and sustainable.

Double Bonus: We hear it all the time… Our Racerback Sports Bra is the high-five you need to crush your next PR.

COMPLETE THE SET

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PERFORMANCE WITHOUT COMPROMISE

Designed for superior performance and maximum comfort—it all starts with Merino wool. Super-soft, ultra-fine Merino wicks sweat to keep you dry, fresh, and funk-free. The natural crimp of its fiber traps air so you stay cool when things heat up and keep warm when there’s a chill.

Moisture wicking

Naturally breathable

Temperature regulating

Benefits of Merino wool icon: Odor-resistant quality of seamless Merino wool

Odor Resistant

BUTTERY SOFT NATURAL FIBER

GYNECOLOGIST APPROVED