Custom Sports Bra Manufacturing: Everything You Need to Know

Sports bras are one of the most technically complex garments in the activewear category, and they are also one of the most lucrative. A well-designed sports bra with the right fit and fabric can become the product that defines your brand. Customers who find a sports bra they love become fiercely loyal — they buy multiples, they recommend to friends, and they follow the brand across seasons.

But get it wrong and the backlash is equally strong. A sports bra that lacks support, digs in, causes shoulder strap marks, or loses its shape after a few washes will generate negative reviews that stick around for years.

Having produced custom sports bras for fitness brands at various price points, I can tell you the key variables that determine whether your sports bra is a bestseller or a return nightmare. Let me walk you through all of them.

Support Levels and Who They Are For

Before you think about fabric or design, you need to decide what support level you are targeting. This fundamental decision shapes almost every other manufacturing choice.

**Low impact support**

Designed for yoga, pilates, stretching, walking, and light activity. These rely primarily on compression from the fabric rather than any internal structure. Construction is relatively simple — a wide underband, wide straps or racerback design, and no underwire or molded cups. The fabric does the work. These are the easiest and least expensive to manufacture.

**Medium impact support**

Designed for cycling, strength training, hiking, and moderate cardio. These typically incorporate a wider underband with more rigid structure, often with a fold-over or separate sewn band with elastic. Straps are usually adjustable. Some styles include removable pads for light shaping. Medium impact bras represent the sweet spot for most fitness brands — they work for a wide range of activities and are not prohibitively complex to produce.

**High impact support**

Designed for running, HIIT, and high-movement activities. These require engineering-level design — encapsulation cups (where each breast is contained in a separate molded cup), underwire in some designs, internal boning or rigid elements, and significantly more complex construction. If you are targeting runners or high-intensity athletes, this is your category. Manufacturing cost and complexity is substantially higher.

For most brands launching a first sports bra, I recommend starting with medium impact. It serves the widest customer base, the manufacturing is manageable, and you can always add a high-impact style once you have established your fit block.

Fabric Selection for Custom Sports Bras

Sports bras need fabric that does several things simultaneously: stretch and recover, manage moisture, maintain opacity, and hold its shape under repeated stress and washing. The main options are:

Nylon-spandex (78% nylon, 22% spandex): The premium choice. Soft, durable, resists pilling, maintains color well. Chlorine-resistant for brands targeting swimmers or pool-based training. More expensive than polyester equivalents but delivers a premium hand feel. Target 200 to 220 GSM for the main body.

Polyester-spandex (88% polyester, 12% spandex): More affordable, excellent moisture management, takes sublimation printing well. A solid choice for mid-tier price points. The same GSM range applies.

Power mesh or perforated panels: Often used in combination with the main fabric for ventilation zones — typically along the back panel or underarm areas. Power mesh adds breathability without sacrificing stretch.

For the underband specifically, you want fabric with higher spandex content (sometimes 20 to 30%) to maximize recovery and hold. Some manufacturers use a separate elastic tape sewn into the underband channel — this adds structure and prevents the band from rolling up during exercise.

Internal Construction Elements

The internal structure of a sports bra is what separates a truly functional garment from one that just looks like a sports bra.

Removable pads: Foam pads inserted into internal pockets provide both modesty and light shaping. The pads should be molded (pre-shaped to breast contour) rather than flat foam. Molded pads fit more naturally and do not crinkle or fold during movement. Specify pocket size and pad dimensions in your tech pack, and make sure the pocket opening is large enough to remove and reinsert the pads easily for washing.

Underwire channel: If you are going high impact, an underwire adds structure and encapsulation support. The wire sits in a sewn channel along the bottom of each cup. This adds significant complexity to manufacturing — the wire needs to be precisely shaped, the channel needs to be reinforced at the ends to prevent poking through, and sizing becomes much more precise.

Boning or stays: Vertical or diagonal rigid elements can be added to prevent the bra from riding up or twisting. More common in higher-end high-impact designs.

Interior lining: Many quality sports bras have a secondary lining layer that sits against the skin, separate from the outer fabric. This allows you to use a performance inner liner (often softer or more moisture-wicking) while using a more fashion-forward outer fabric.

Strap and Back Design Options

The back and strap design is both a functional and aesthetic decision.

Racerback: The most common sports bra back. Straps converge toward the center of the back, which keeps them in place during movement and distributes weight across the upper back. Available in T-back, Y-back, and lattice variations.

Straight back with adjustable straps: More similar to a traditional bra construction. Adjustable straps allow for fit customization. More complex to manufacture due to the adjusters and hooks. Better for medium to high impact where precise fit adjustment matters.

Longline designs: The bra extends down the torso (usually 4 to 8 cm below a standard underband). Popular in yoga and pilates categories. Often serves double duty as both a bra and a crop top for the studio-to-street market.

Cut-out and detail backs: Open back designs, strappy details, and mesh panels are fashionable options for studio wear. They look beautiful but require more construction steps. If you are going this route, make sure your manufacturing partner has experience with these constructions and factor in the additional cut-and-sew time.

Sizing Considerations

Sports bras can be sized in two ways: by letter/number bra sizing (32A, 34B, etc.) or by S/M/L/XL sizing. For low and medium impact bras, S/M/L/XL sizing works well and simplifies manufacturing — it means fewer size variations and larger per-size order quantities. For high-impact bras with structured cups, letter/number sizing provides better fit precision but dramatically increases the size matrix.

If you are starting out, S/M/L/XL sizing is the practical choice. You can always add a structured, properly-sized line later once you understand your customer base.

Size inclusivity is increasingly important in the fitness market. Consider extending your range to include a 2XL or even 3XL from the beginning — this opens up a significant underserved market and signals brand values that resonate with customers.

Branding Your Sports Bra

Branding options for sports bras include woven labels on the underband (the standard location), embroidery on the front chest area or strap, heat transfer labels to eliminate any label that might scratch skin, and sublimation or screen-printed graphics on the back panel.

One underutilized branding location is the inside of the waistband — a bold brand name or tagline printed on the interior edge creates a delightful moment when the customer puts the bra on, and often shows up in social media "getting dressed" content.

The underband label is typically your care and content label. Make sure it is printed on soft, skin-friendly material, or better yet, use a heat transfer label to eliminate any roughness against skin.

If you are ready to start developing your custom sports bra line, explore fitness wear for inspiration and examples of what we produce. Then get a free quote with your specific requirements — we start at just 50 pieces per style and our team responds within 24 hours.