Silicone, latex or fabric: what your cap is made of

Most swimming caps here are silicone. Arena says its silicone cap fits all head shapes, protects hair from chlorine and is easy to put on and take off. Nike gives its Big Swoosh cap a textured lining for extra grip.

Latex is the other stretchy option. TYR makes its Latex Swim Cap with a ribbed edge and says it reduces drag and resists tearing. Fabric caps are the easiest to wear. Arena's Light Sensation II is made from a coated elastic fabric, it is easy to put on and take off, and Arena recommends it for fitness swimming. Speedo also makes a polyester cap for kids.

Long hair: pick a cap with extra room

A standard cap can feel tight over long or thick hair, so several caps here are cut bigger. Nike's Solid Long Hair Silicone Training Cap has extra space for long hair, and TYR's Long Hair Silicone Cap has an enlarged, asymmetrical shape. For young swimmers, Speedo's Junior Long Hair caps add extra depth for thick or long hair. Arena's Sirene is a moulded silicone cap made for long hair.

Moulded or flat: how the cap sits on your head

Moulded caps are shaped in 3D. Arena says the moulding on its Poolish caps gives a smooth, wrinkle-free surface that improves glide, and TYR says its Wrinkle-Free caps reduce drag in the water. Flat-moulded caps like the Arena Print II have a classic fit, with a reinforced edge that stops the cap riding up.

Almost every cap here is one size. The exception is the Speedo Fastskin, sold in S, M and L and built on head-mapping data.

If you swim for fitness, start with a classic silicone cap from Arena. If you have long hair, choose a long hair cap, and pair it with swimming goggles.