Speedo Caps

Choosing the Right Speedo Swim Cap

A cap is one of the smallest pieces of kit in a swim bag, yet it does more work than almost anything else on this page. It keeps hair contained, cuts resistance through the water, and for many swimmers marks the difference between a comfortable session and a distracting one. Speedo has been refining swim cap design for decades, and the range at Allens Swimwear reflects that experience, covering everyday silicone caps, ergonomic Biofuse designs, generous long hair styles, and the low-profile Fastskin Hiro built for race day.

Silicone, Biofuse and Polyester: Understanding Speedo's Cap Materials

Most swimmers reach for a silicone swim cap by default, and there's a good reason for that. Speedo's Plain Moulded, Flat Silicone and Multi Colour caps create a snug, water-resistant seal that holds its shape season after season, standing up to regular chlorine exposure far better than fabric alternatives. Within the silicone range, Speedo's Biofuse Solid caps take this a step further with a more ergonomic, contoured shape designed to sit naturally against the head rather than pulling tight at the temples, which some swimmers find more comfortable across a long training set.

Polyester caps sit at the other end of the range. They won't reduce drag or repel water the way silicone does, but they're lighter, more breathable, and don't grip hair as firmly, which makes them a popular choice for swimmers with a sensitive scalp, thinner hair, or those who simply find silicone caps too tight. Neither material will keep hair completely dry. What changes between them is how much water gets through and how the cap feels over the course of a session.

Long Hair and Long Hair Volume Caps

Standard caps are cut for shorter hair, so anyone with hair past the shoulders, a bun, or braids often finds a regular cap stretches, slips, or feels uncomfortably tight within the first few lengths. Speedo's Long Hair cap adds extra internal room to solve this, and the Long Hair Volume goes further still for very thick or long hair. Both are built to stay in place through tumble turns and race starts rather than working loose mid-session, which matters as much for a club swimmer training four times a week as it does for a competitive swimmer on race day.

Speedo Fastskin Hiro: Built for Race Day

The Fastskin Hiro sits apart from the rest of the training range. It's shaped with a low-profile, hydrodynamic design intended to reduce drag from the moment of the dive through every turn, rather than prioritising the all-day comfort a training cap needs. It's part of the same Speedo Fastskin family as Speedo's race suits and racing goggles, so competitive swimmers already wearing Fastskin swimwear often pair it with the Hiro cap for a consistent race-day setup.

Which Speedo Cap Should You Choose?

• Training several times a week: a Plain Moulded Silicone or Biofuse Solid cap for a fit that holds up to regular chlorine exposure.
• Long or thick hair: the Long Hair or Long Hair Volume cap, for extra room without the cap working loose.
• Racing at club galas or championships: the Fastskin Hiro, for a low-profile fit built around race performance.
• Sensitive scalp or a lighter feel: a Polyester cap, which grips hair less firmly than silicone.
• Wanting to stand out on poolside: the printed and Multi Colour Silicone designs.

Caring for Your Swim Cap

A little care goes a long way with any swim cap. Rinsing in fresh water after a session removes chlorine before it has a chance to work on the material, and drying the cap fully before folding it away helps it keep its shape and stretch for longer. Storing a cap folded while still damp is one of the most common reasons silicone starts to crack or lose elasticity early. If a cap begins to feel less stretchy, develops small tears, or no longer holds a snug fit, that's usually the sign it's due for a replacement.

Sizing and Fit

Speedo's swim caps use a stretch-fit design intended to suit most adult head sizes, so there's no separate sizing chart to work through. The main decision is style rather than size: Long Hair and Long Hair Volume caps add room for hair rather than head circumference, and Polyester caps tend to sit slightly looser around the ears than silicone.

Frequently Asked Questions

What is the difference between a silicone and a fabric swim cap?

Silicone caps create a tighter, more water-resistant seal that reduces drag and holds its shape through regular chlorine exposure, which is why most competitive and regular training swimmers choose them. Polyester (fabric) caps are lighter and don't grip hair as tightly, so they suit swimmers who find silicone uncomfortable or who swim less often. Neither type will keep hair completely dry, since no swim cap is fully waterproof.

Do I need a special cap for long hair?

If your hair sits below your shoulders or you tie it in a bun, a standard cap will usually stretch, slip, or feel uncomfortably tight. Speedo's Long Hair and Long Hair Volume caps add extra internal room, so they stay in place through turns and full training sessions.

How long do swim caps usually last?

This depends on how often you swim and how the cap is cared for, but silicone caps generally hold their shape and stretch for longer than fabric when rinsed and dried properly after each use. Once a cap starts to feel less elastic, develops small tears, or no longer holds a snug fit, it's a sign it needs replacing.

What makes the Speedo Fastskin Hiro different from a training cap?

The Fastskin Hiro is built with a low-profile, hydrodynamic shape designed to reduce drag on race day, rather than for the all-day comfort a training cap needs. It's part of Speedo's wider Fastskin range, so many competitive swimmers pair it with Fastskin swimwear and goggles for a consistent race-day setup.

Will a swim cap keep my hair completely dry?

No swim cap, including silicone options, is fully waterproof, so some water will usually get through at the edges. What a good cap does is reduce how much water reaches your hair and keep it out of your face, rather than eliminating water contact entirely.

Can I wear a Speedo swim cap for open water swimming?

Speedo's silicone caps can be worn for open water sessions, but they don't offer the thermal protection a neoprene cap provides in cold water. Swimmers doing regular open water or cold-water sessions often choose a neoprene option instead.

More From Speedo

This collection covers Speedo's full swim cap range, from everyday training caps through to race-ready options. For the rest of Speedo's kit, browse the full Speedo collection or pair your cap with Speedo swimming goggles. Younger swimmers may find a better fit in our kids swimming caps, and for a broader comparison of materials and styles across every brand we stock, see our full swimming caps range. Allens Swimwear is an authorised UK stockist for the full Speedo range, and orders over £40 qualify for free UK delivery.