Wetsuit — What It Is and Why It Matters
A wetsuit is a form-fitting neoprene garment that provides thermal insulation for scuba divers by trapping a thin layer of water between the suit and the skin. Body heat warms this water layer, which then acts as insulation against the surrounding cold water. Wetsuits range from 1mm shorties for tropical waters to 7mm full suits with hoods for cold-water diving.
Proper fit is critical — a wetsuit that is too loose allows constant water exchange (flushing), eliminating the warming effect. Modern wetsuits use sealed seams, smooth-skin neoprene panels, and chest zippers to minimize water entry. Wetsuit thickness and coverage should be matched to the water temperature you are diving in.
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Frequently Asked Questions
What thickness wetsuit do I need?
General guidelines: tropical water above 27°C (80°F) — 1 to 3mm or rashguard; warm temperate 21 to 27°C (70 to 80°F) — 3 to 5mm; cool temperate 15 to 21°C (59 to 70°F) — 5 to 7mm; cold below 15°C (59°F) — 7mm or drysuit. Individual cold tolerance varies significantly.
Does wetsuit neoprene compress at depth?
Yes. Neoprene compresses with increasing pressure, reducing both its insulation and buoyancy. A 5mm wetsuit at 30 meters provides significantly less warmth than at the surface. This is why deep or cold-water divers often prefer drysuits, which maintain insulation regardless of depth.
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