Freediving Wetsuit Thickness Guide - What to Wear at Every Temperature

Wetsuit thickness is the most important variable in staying warm underwater. Get it right and you dive comfortably for hours. Get it wrong and you're shivering after 20 minutes. Thickness also directly affects buoyancy — the thicker the neoprene, the more lead you need to compensate.

Closed-Cell

Construction

fabric lining inside and outside

Durability

more durable — resists tearing on rocks and surfaces

Ease of use

easier to put on — no lubrication needed

Warmth

slightly less warm per millimeter than open-cell

Best for

beginners — learn in closed-cell, switch to open-cell when the suit gets regular use

Open-Cell

Construction

bare foam on the inside — bonds directly to skin

Warmth

significantly warmer — 10–15% more per millimeter

Flexibility

better streamlining and arm mobility for duck dives

Fragility

tears easily with fingernails — requires suit lube to put on

Best for

regular divers at 5mm and above where the warmth difference becomes meaningful

Two-piece (jacket + pants with integrated hood)

double neoprene over the core — significantly warmer. Integrated hood eliminates neck seal gap. Better choice for any water below 22°C.

One-piece

simpler to put on, less expensive. Fine for warm water (24°C+).

Every millimeter of neoprene adds buoyancy. Compensate with lead:

Always verify with a pool test before open water diving in a new suit.

Hood

head and neck lose disproportionate heat — below 20°C, a hood is not optional. Most two-piece cold-water suits have an integrated hood.

Gloves

at 15°C and below, bare hands become painful and clumsy quickly — 3mm neoprene gloves add meaningful warmth

Boots

for shore diving on rocks, and for insulation in water below 18°C

• Rinse with fresh water after every session — inside and out
• Dry in shade — direct sun degrades neoprene
• Store flat or on a wide hanger — thin hangers crease the material
• Don't leave in a hot car
• For open-cell: use suit lube or conditioner for donning — never pull with dry fingernails

A quality freediving wetsuit lasts 3–5 years with basic care.