Funky Trunks Mens Size Guide

This size guide covers Funky Trunks Men's Training Swimwear, including the Classic Trunk, Sidewinder Trunk, Classic Brief, and Training Jammer. All styles are made from Funky Trunks' exclusive C-Infinity or ECO C-Infinity fabric — 100% Italian polyester with 100% chlorine resistance, high-definition colour fastness, and 50+ UV sun protection. Fabric milled in Italy.

Size based on chest, waist, and hip measurements. Funky Trunks men's swimwear is available in sizes XS–XXL (UK 30–40).

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How to Measure — Funky Trunks Men's
How to measure for Funky Trunks men's swimwear

Measure in centimetres with a soft tape measure taken directly against the skin or over light underwear. Use all three measurements to find the best fit in the table below.

  • Chest — measure around the fullest part of the chest, under the armpits, keeping the tape parallel to the floor.
  • Waist — measure around the narrowest part of the waistline, usually just above the belly button. Keep the tape parallel to the floor.
  • Hips — measure around the fullest part of the hips and seat, keeping the tape parallel to the floor.
  • If measurements fall between two sizes, speak to a member of staff at Allens for advice on the best fit for the specific style.
Size XS S M L XL XXL
UK 30 32 34 36 38 40
US 30 32 34 36 38 40
AUS XS / 30 S / 32 M / 34 L / 36 XL / 38 XXL / 40
France 1 2 3 4 5 6
Body Measurements (cm)
Chest (cm) 86–92 92–97 97–103 103–108 108–113 113–118
Waist (cm) 75–80 80–85 85–90 90–95 95–100 100–105
Hips (cm) 80–85 85–90 90–95 95–100 100–105 105–110

UK and US numeric sizes are equivalent. AUS sizes are shown as both letter and number. Use waist and hip measurements as the primary guide for trunks and briefs. If between sizes, speak to a member of staff at Allens.

Classic Trunk
  • 14cm sides with a single front panel and full front lining.
  • Drawcord waist with wide elastic leg opening and waistband for comfort.
  • C-Infinity fabric — 100% chlorine resistant, 50+ UV, milled in Italy.
Sidewinder Trunk
  • 8cm sides — a classic cut brief with full front lining.
  • Drawcord waist with wide elastic leg opening.
  • C-Infinity fabric — 100% chlorine resistant, 50+ UV, milled in Italy.
Classic Brief
  • 16.5cm sides with a stitched front pouch and double lining for support.
  • Drawcord waist with wide elastic leg opening and waistband.
  • C-Infinity fabric — 100% chlorine resistant, 50+ UV, milled in Italy.
Training Jammer
  • Hip-to-knee coverage with flatlock stitching and front pouch lining.
  • Drawcord and flat elastic waistband for a secure fit during dives and turns.
  • ECO C-Infinity fabric — made from recycled plastic bottles, 100% chlorine resistant, 50+ UV.
Fit Notes — Funky Trunks Men's Swimwear
  • Use waist and hip measurements as the primary guide for trunks and briefs. For the Training Jammer, also consider the hip measurement to ensure comfortable coverage from hip to knee.
  • The Classic Brief (16.5cm sides) is the widest trunk option — suited to swimmers who prefer greater hip coverage. The Sidewinder (8cm sides) is the most minimal cut. The Classic Trunk (14cm) sits between the two.
  • All styles feature a drawcord waist for an adjustable, secure fit. Ensure the drawcord is tied before entering the water.
  • C-Infinity and ECO C-Infinity fabrics are 100% chlorine resistant and built for regular training. 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 — Funky Trunks Men's Swimwear

Measure your chest, waist, and hips in centimetres and match to the size table above. UK sizing is the primary reference — US, AUS, and France equivalents are also shown. For trunks and briefs, use waist and hip as the primary guide. If your measurements fall between two sizes, speak to a member of staff at Allens for advice.

The Classic Brief has 16.5cm sides with a stitched front pouch and double lining — the widest cut and most supportive. The Classic Trunk has 14cm sides with a single front panel and full front lining — a versatile mid-length trunk. The Sidewinder is a brief-style cut with 8cm sides and full front lining — the most minimal option. The Training Jammer provides hip-to-knee coverage with flatlock stitching — designed for swimmers who prefer full-leg coverage during training.

C-Infinity is Funky Trunks' exclusive 100% Italian polyester fabric, offering 100% chlorine resistance, high-definition colour fastness, and 50+ UV sun protection. It is designed to retain its strength and durability far beyond other elastane swimwear fabrics, making it the superior choice for swimmers who train frequently. ECO C-Infinity is the same fabric manufactured from recycled end-of-life plastic water bottles.

The Funky Trunks Training Jammer is a training swimsuit designed for regular pool use and is not a World Aquatics-approved racing suit. For competitive racing, a FINA-approved race suit is required. The Training Jammer is, however, an excellent choice for club training, squad sessions, and performance-focused training where hip-to-knee coverage is preferred.

Rinse in cold fresh water after every session to remove chlorine and salt. Allow to dry naturally away from direct sunlight — do not tumble dry or wring. The C-Infinity and ECO C-Infinity fabrics are 100% chlorine resistant and built for regular pool use. With proper care the prints and fabric will maintain their quality for longer.

For competitive training, the Training Jammer is the closest to a race-day fit, offering hip-to-knee coverage with flatlock stitching and a front pouch lining designed for speed and comfort. Swimmers who prefer a shorter cut for training often choose the Sidewinder or Classic Trunk. The Classic Brief suits swimmers who prefer wider sides and additional support. Speak to a member of staff at Allens if you are unsure which style best suits your training.

Flatlock stitching is a technique where the seams lie flat against the skin rather than forming a raised ridge. This minimises rubbing and irritation during training sessions, contributes to a smoother feel in the water, and is a hallmark of performance swimwear construction.

ECO C-Infinity is Funky Trunks' sustainable version of their C-Infinity fabric, manufactured from end-of-life plastic water bottles. It delivers the same 100% chlorine resistance, 50+ UV protection, and colour fastness as standard C-Infinity, while reducing environmental impact by repurposing waste plastics. It is used in the Training Jammer range.