Speedo Junior Fastskin Endurance+ Max Jammer Size Guide

Our World Aquatics-approved Fastskin Junior Endurance®+ Max High Waisted Jammer emulates the style lines of our popular LZR Valor suit, so young swimmers can look and feel like their swim heroes as they step up to the blocks. Designed specifically for young swimmers, the jammer features a bold colour-block design. Its flatlock seams and 4-way stretch fabric ensure comfort and freedom of movement, allowing junior athletes to focus on their race. Built to last, it’s chlorine resistant, quick-drying, and designed to withstand everything their race day swim sessions throw at it.

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Body Measurement Points
Boys body measurement guide showing waist and hip measurement points
How to Measure

To find the correct size, use a soft measuring tape and take all measurements directly against your child’s skin. Always use body measurements — age is shown as a guide only, as children develop at different rates.

  • B
    Waist Measure around the natural waistline at the narrowest point of the torso, keeping the tape parallel to the floor.
  • A
    Hips Measure around the fullest part of the hips and seat, keeping the tape parallel to the floor. Use this as the primary sizing measurement where waist and hip suggest different sizes.

Note: Ages shown in the sizing table are a guide only. Always measure and use body measurements to select the correct size.

Sizing Table — Speedo Boys’ Fastskin Junior Endurance®+ Max High Waisted Jammer
Size 24 Size 26 Size 28 Size 30 Size 32 Size 34
Age (guide only) 5–6 yrs 7–8 yrs 9–10 yrs 11–12 yrs 13–14 yrs 15–16 yrs
Body Measurements
Waist cm 58 61.5 66 71 76 81
Hips cm 65 70 75 81.5 88 94.5

All measurements are body measurements, not garment measurements. Speedo racing suits are designed to fit snugly — if between sizes, we recommend sizing up. Contact Allens if you need guidance.

Fit Notes — Speedo Boys’ Fastskin Junior Endurance®+ Max High Waisted Jammer
  • Size based on waist and hip measurements. For boys, both measurements should be checked against the table — where they suggest different sizes, prioritise the hip measurement for the most comfortable fit in the lower body.
  • Fastskin racing jammers are designed to fit tighter than training jammers. Some initial resistance when pulling the suit on is normal and is not a sign that it is too small.
  • The high waist panel should sit firmly at the natural waist without rolling down or digging in.
  • Allow 10–15 minutes to try on correctly for the first time. Take care with fingernails when pulling up the suit to avoid damaging the fabric.
  • Constructed from Endurance+ Max chlorine-resistant fabric — rinse in cold fresh water after every session and allow to dry naturally away from direct sunlight.
  • Unsure? Contact our team or call +44 1827 330600.
Frequently Asked Questions — Speedo Boys’ Fastskin Junior Endurance®+ Max High Waisted Jammer

Measure the waist and hips in centimetres and match to the size table above. Where measurements suggest different sizes, prioritise the hip measurement. Speedo racing jammers are designed to fit snugly, so some compression is expected. If measurements fall between sizes, size up, particularly for younger swimmers still growing.

Yes. The Fastskin Junior Endurance®+ Max High Waisted Jammer is World Aquatics approved and legal for use in sanctioned competitions. Always check with your club or event organisers to confirm the specific approval requirements for your level of competition.

The Fastskin Junior Endurance®+ is a racing jammer, not a training suit. It is designed for competition with a closer, more compressive fit, low-profile flat lock seams to minimise drag, and a high waisted cut that mirrors the adult LZR Valor style. The Endurance+ Max fabric means it can also handle regular training sessions, but its primary purpose is race performance.

The size range covers UK ages 5–6 years (size 24) through to 15–16 years (size 34). Always size based on measurements rather than age alone, as fit can vary considerably between swimmers of the same age.

Yes. Racing jammers are designed to fit considerably tighter than training jammers. Some resistance when pulling the suit on is entirely normal and does not mean it is too small. Once on, the jammer should feel compressive but should not restrict breathing or circulation. If the swimmer is uncomfortable in the water, consider sizing up.

Roll the jammer from the legs upward, working it gradually up the body rather than pulling from the waistband. Take care around the seams and fabric panels — do not pull sharply or use fingernails, as this can damage the material. Wetting the jammer or the skin slightly can help ease it on. Allow at least 10–15 minutes to put the suit on before racing.

Rinse in cold fresh water immediately after use to remove chlorine and salt. Do not wring, tumble dry, or expose to direct sunlight for extended periods. Lay flat or hang to dry naturally. Avoid sitting on rough pool surrounds while wearing the jammer, as this can cause abrasion to the fabric panels.