Why Wetsuit Thickness Matters
A wetsuit works by trapping a thin layer of water between your skin and the neoprene. Your body heats that water; the insulating foam keeps it warm. Too thin a wetsuit in cold water = hypothermia risk. Too thick in warm water = overheating and restricted movement. Getting the thickness right is the most important wetsuit decision.
Thickness Guide
| Water Temp | Recommended Thickness | Notes |
|---|---|---|
| 75°F+ (24°C+) | No wetsuit / Rashguard | Only UV protection needed |
| 65-75°F (18-24°C) | 2mm springsuit or 2/2 fullsuit | Summer surf in most US coastal areas |
| 58-65°F (14-18°C) | 3/2mm fullsuit | Most popular all-around thickness |
| 50-58°F (10-14°C) | 4/3mm fullsuit + hood | Northern California, Pacific NW, UK |
| Below 50°F (10°C) | 5/4/3mm + hood + boots + gloves | Cold water surfing, ice diving |
Wetsuit Styles
- Springsuit (shorty): Short arms and legs. Best for 65-75°F, maximum mobility. Popular for warm-water surfing and kayaking.
- Fullsuit (steamer): Full arms and legs. The standard for most surfing, diving, triathlon. Available 2/2 to 5/4/3.
- Triathlon wetsuit: Thinner arms (1.5-2mm) for freestyle swimming arm rotation. Thicker core (3-5mm) for buoyancy. Designed for swim-bike-run transitions with full-length zipper.
- Dive wetsuit: Thicker overall, often 7mm for deep/cold diving. Knee and seat padding. Not suitable for swimming or surfing.
Seam Technology
- Flatlock stitching: Overlapping panels sewn flat. Lightest and most flexible, but seams allow water penetration. Best for warm water (65°F+).
- Glued and blindstitched (GBS): Seams glued shut and blindstitched (needle doesn't penetrate outer surface). Much warmer than flatlock. Standard for 3/2mm+ suits.
- Taped seams: Liquid tape applied over GBS seams for additional waterproofing. Best for cold water suits (4/3mm+).
Fit Guide
A properly fitting wetsuit should be snug but not constricting. Signs of poor fit: water flushing freely in and out at neck/wrists/ankles (too large), difficulty breathing or raising arms overhead (too small). Measure chest, waist, and height; then cross-reference the brand's sizing chart — sizing varies significantly between brands.
Wetsuit sizing: O'Neill sizes are typically generous. Rip Curl sizes are slightly smaller. Xcel runs true-to-size. When between sizes, go smaller — neoprene stretches over time.