Choose the right cap

Key aspects to consider when purchasing your next cap depend on the demands of your chosen sport. The structural elements differ mainly due to sweat volume, UV exposure, fit (stability), as well as brim shape and length. This guide breaks down materials, sport-specific designs and UPF ratings so you can match the cap to the way you play.

Materials to consider

A good starting point is recycled polyester mesh and/or recycled nylon. As covered in our rPET sports tops article, rPET performs in exactly the same way as virgin polyester. When comparing wicking and quick-dry properties, rPET is used extensively in running caps specifically for these benefits.

Recycled nylon — made from fishing nets and industrial nylon waste — can be used for structural panels thanks to its abrasion resistance. The trade-off with these materials is the shedding of microplastics across the product life cycle.

Cotton (non-organic) is conventionally used in sweatbands and lifestyle tennis caps for its soft, absorbent and breathable qualities. The water footprint of cotton is considerable, though, and it can be pesticide intensive. Cotton retains moisture instead of wicking it, which is a functional downside after prolonged use in one session. Tencel has lower environmental trade-offs and has become a preferred option, using up to 20x less water.

GOTS-certified organic cotton twill, or a hemp blend (which can reduce softness), gives a structured, breathable, classic look. It holds the flatter, longer-brim shape well. Golf caps generally use more material due to the design of a fuller, higher crown and longer brim alongside an adjustable snapback. Given the nature of golf, head movement is less dynamic, and comfort over many hours takes priority over stability. Visors are an alternative that traps less heat and gives more ventilation.

Tennis caps usually use rPET or recycled nylon (for the structured panels as the abrasion-resistant material) in the shell, as the structure needs to be flexible with a secure strap or velcro closure. Stability has to withstand rapid lateral head movement and direction changes without shifting. For the sweatband, a lightweight Tencel or lyocell blend is a soft choice whose moisture-absorbent properties also reduce the weighty feel cotton takes on once moisture sets in.

Fast-wicking properties are imperative to stop sweat dripping into the eyes and affecting play. The brim also needs to accommodate upward sightlines — especially for serves and overhead shots — which is why a short-to-medium, moderately curved brim has become the design standard.

With the highest sweat volume of the three sports, the cap itself needs to be highly absorbent, wicking and/or mesh, usually in a full-crown design. rPET mesh is a very good match for performance and perforation tolerance within the shell. There is generally more structure built into the sweatband to take advantage of its wicking properties.

The requirements of light weight, maximum airflow and effective wicking make rPET mesh a great solution, with the addition of eyelets to manage heat build-up during longer runs. To maximise speed, the brim needs to be short to reduce drag — resulting in the short, tightly curved, minimalist design that defines the category.

An Ultraviolet Protection Factor — UPF — rating grades fabrics by how much UV radiation passes through. A UPF rating of 30 permits roughly 3% of UV radiation through, while UPF 50 permits about 2%. Anything under UPF 15 isn't considered UV-protective at all, and a typical white cotton t-shirt is around UPF 5. Synthetic fibres like polyester (rPET) and nylon scatter and absorb UV naturally, so tight synthetic knits often reach UPF 40–50 without any chemical treatment.

Based on this: recommended caps

FAQ

What is the best material for a running cap?

Recycled polyester (rPET) mesh is the strongest all-round choice for running caps: it wicks sweat, dries fast, tolerates perforation in the shell design and pairs well with eyelets for heat management. Running has the highest sweat volume of the three sports, so lightweight airflow matters more than structure.

What UPF rating do I need in a sports cap?

Anything under UPF 15 is not considered UV-protective. Golf warrants the highest target — UPF 50 — given multi-hour mid-day exposure. Tennis sits around UPF 30–50, and running benefits from UPF 40–50+. Tight synthetic knits like polyester (rPET) and nylon often reach UPF 40–50 without chemical treatment because the fibres naturally scatter and absorb UV.

Is cotton a good material for sports caps?

Conventional cotton is soft, absorbent and breathable, which is why it appears in sweatbands and lifestyle tennis caps. However, it retains moisture instead of wicking it — a functional downside in long sessions — and carries a considerable water footprint and pesticide intensity. Tencel (lyocell) uses up to 20x less water and is a preferred lower-impact alternative.

Why do tennis caps have shorter, curved brims?

Tennis demands clear upward sightlines for serves and overhead shots, so a short-to-medium, moderately curved brim has become the design standard. Stability also matters: a secure strap or velcro closure keeps the cap from shifting during rapid lateral head movement and direction changes.