Wetsuit Thickness
Water & Snow · 9 specs
Direct Answer
Wetsuit thermal insulation is defined by closed-cell neoprene thickness in millimeters, designated as a dual or triple number (e.g. 3/2 mm, 4/3 mm, 5/4 mm, 6/5/4 mm). The first (larger) number denotes the torso/core thickness for vital organ warmth; the secondary number denotes the limb/arm thickness for paddling flexibility. Temperature ratings range from 2 mm / shorties (20–25 °C / 68–77 °F) to 5/4 mm and 6/5 mm hooded suits with liquid-taped seams for sub-arctic water (sub-8 °C / sub-46 °F).
Source: ISO 18830 (Diving equipment–Wet suits) / Surfing Industry Technical Guidelines · Last reviewed Aug 28, 2026
Specs
| 2 mm / Shorty Temperature Range | 20.0–25.0 °C (68.0–77.0 °F warm summer water) |
| 3/2 mm Fullsuit Temperature Range | 15.0–20.0 °C (59.0–68.0 °F spring/autumn water) |
| 4/3 mm Fullsuit Temperature Range | 12.0–15.0 °C (53.6–59.0 °F cool water standard) |
| 5/4 mm (with Hood) Temperature Range | 8.0–12.0 °C (46.4–53.6 °F cold winter water) |
| 6/5 mm / 6/5/4 mm Hooded Winter Range | Sub-8.0 °C (sub-46.4 °F arctic / freezing water) |
| Primary Material Composition | Closed-Cell Nitrogen-Blown Limestone Neoprene (Chloroprene Rubber) Standard |
| Flatlock Seams | Breathable stitch for 2 mm warm-water suits (water permeates seam) Warm Water |
| GBS (Glued and Blindstitched) | Water-tight glued seams with curved needle blindstitching (3/2 & 4/3) Cool Water |
| Liquid Taped / Fluid Seam Weld | External liquid silicone/polyurethane bead over internal neoprene tape Cold Water Fully Sealed |
Dual-Number Thickness Architecture & GBS Seams
- Torso Core vs. Limb Flexibility (3/2 mm & 4/3 mm): A 4/3 mm wetsuit uses 4 mm neoprene across the chest, back, and lumbar regions to protect internal core body temperature from conductive thermal loss, while using 3 mm neoprene on the shoulders, arms, and legs to preserve paddling stroke range of motion.
- GBS vs. Liquid-Taped Seams: Standard flatlock stitching pierces completely through the rubber, admitting cold water flushes. Glued and Blindstitched (GBS) seams penetrate only halfway through the neoprene from one side before being sealed with vulcanized elastic seam tape.