Arena Aquaforce Racing Swimming Cap

This size guide covers the Arena Aquaforce Cap. The Arena Aquaforce is a high-performance silicone swimming cap engineered for competitive swimmers. Its advanced construction uses two measurements — head circumference (A) and ear-to-ear measurement (B) — to ensure a precise, streamlined fit that reduces drag and stays firmly in place throughout the race. Available in three sizes: M, L, and XL.

Select your size by taking both measurements and comparing to the sizing table below. If your measurements suggest different sizes, use the ear-to-ear measurement (B) as the primary guide.

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How to Measure
Arena Aquaforce Cap head circumference and ear-to-ear measurement diagram
Measurement Guide

Use a soft tape measure to take both measurements. Use the ear-to-ear measurement (B) as the primary guide if measurements suggest different sizes.

  • A
    Circumference of the HeadMeasure around the widest part of the head, just above the eyebrow, keeping the tape horizontal and level all the way around.
  • B
    Ear-to-EarMeasure from the top of one ear, over the crown of the head, to the top of the other ear. Keep the tape close to the head throughout.

If your two measurements suggest different sizes, use the ear-to-ear measurement (B) as the primary guide. Speak to a member of staff at Allens if you are unsure.

Sizing Table — Arena Aquaforce Cap
Measurement M L XL
Body Measurements (cm)
A — Head Circumference 45 45 45
B — Ear-to-Ear 33 33.5 39

All sizes share the same head circumference (45 cm). Use the ear-to-ear measurement (B) to distinguish between M, L, and XL. All measurements are in cm.

Fit Notes — Arena Aquaforce Cap
  • All three sizes of the Aquaforce share the same head circumference (45 cm) — use the ear-to-ear measurement (B) to select between M, L, and XL.
  • The cap should feel snug but not tight — it should sit flat on the head with no wrinkles or air pockets, and should not pull at the hairline or ears.
  • For competitive use, the cap is typically worn over the goggle strap to keep the straps secure and reduce drag. Pull the cap down firmly over the ears before racing.
  • The high-performance silicone construction is engineered to stay firmly in place during racing with a streamlined, drag-reducing profile.
  • Wet your hair before putting the cap on to make it easier to wear and to create a better seal at the hairline.
  • Rinse in fresh water after every use and allow to dry naturally away from direct sunlight. Store away from sharp objects. Dust lightly with talc if the cap sticks when stored.
  • Unsure? Contact our team or call +44 1827 330600. Speak to a member of staff at Allens if you are unsure.
Frequently Asked Questions — Arena Aquaforce Cap

Take two measurements — your head circumference (A) around the widest part of the head just above the eyebrow, and your ear-to-ear measurement (B) from the top of one ear over the crown to the top of the other ear. All three Aquaforce sizes share the same head circumference (45 cm), so use the ear-to-ear measurement to select between M, L, and XL. Speak to a member of staff at Allens if you are unsure.

The Arena Aquaforce Cap is engineered for a precise, high-performance fit and all three sizes are designed to work with the same head circumference of 45 cm. The ear-to-ear measurement (B) reflects differences in head shape and width — swimmers with the same circumference can have significantly different ear-to-ear proportions. Using both measurements together ensures the best possible fit and performance.

Place one end of a soft tape measure at the top of one ear, then run the tape over the crown of the head to the top of the other ear. Keep the tape close to the head throughout and ensure it follows the natural curve of the skull. This measurement captures the width and depth of the head which, combined with the circumference, gives the most accurate cap sizing.

Yes. The Arena Aquaforce Cap is a high-performance cap designed specifically for competitive swimming. Its construction provides a streamlined, drag-reducing profile that stays securely in place throughout the race. For competition use, pull the cap down firmly over the ears and wear it over the goggle strap. Check with your event organiser for any specific cap rules that may apply at your competition.

The Aquaforce Cap should sit snugly on the head with no wrinkles, air pockets, or gaps at the hairline or ears. It should feel secure and streamlined without causing discomfort or headaches. The cap should not slip during swimming. For the best fit, wet your hair before putting the cap on to create a better seal at the hairline.

The Arena Aquaforce Cap is a high-performance competition cap engineered for maximum drag reduction and a precision fit, sized using both head circumference and ear-to-ear measurements. The Arena 3D Soft Cap is a premium silicone cap with a 3D moulded construction for comfort and wrinkle-free fit, sized using head circumference alone and available in an XL for voluminous hair. Both are suitable for competition, but the Aquaforce is specifically engineered for racing performance.

Yes. The Arena Aquaforce Cap is designed to be worn with swimming goggles. For competitive swimming, the cap is typically worn over the goggle strap to keep the straps secure and reduce drag. Ensure the cap is pulled down firmly over the ears and that the goggle strap is positioned correctly beneath the cap before racing.

Rinse the cap in cold fresh water after every use to remove chlorine and salt. Allow to dry naturally away from direct sunlight — UV exposure can degrade the silicone over time. Store in a cool, dry place away from sharp objects. If the cap sticks to itself when stored, dust lightly with talcum powder. Do not fold or crease the cap when storing.