Australian water temperatures range from 10°C in Tasmanian winter to 30°C on the tropical Queensland coast. Here is how to match wetsuit thickness to your location and activity.
How Wetsuits Work
A wetsuit works by trapping a thin layer of water against your skin, which your body heat warms. The neoprene material then insulates this warm-water layer from the surrounding cold water. The thicker the neoprene, the greater the insulation — but thickness comes at a cost in buoyancy, flexibility, and breathability in warmer conditions.
Fit is more important than thickness. A wetsuit with gaps at the neck, wrists, and ankles flushes cold water continuously and provides little insulation regardless of its rated thickness. A wetsuit that fits correctly — snug against the skin with no significant gaps — of any adequate thickness will be warm. Try wetsuits on in person when possible, or buy from retailers with clear size guides and returns policies.
Thickness Guide for Australian Waters
1–2mm (tropical and subtropical summer): Northern Queensland, NT, and WA coastal waters from September to May. Water temperatures typically 24–30°C. A 1–2mm suit provides sun and jellyfish protection rather than thermal insulation. More comfortable and far more flexible than thicker suits.
3mm (warm temperate): Sydney and northern NSW year-round summer, Queensland winter, SA and WA warmer months. Water 18–24°C. Adequate thermal protection for surface snorkelling and shallow diving for up to 90 minutes.
5mm (cool temperate): Victoria and NSW south coast in summer, SA and WA in cooler months. Water 14–20°C. The standard choice for Victorian summer snorkelling and crayfish diving. Adequate for dives of 30–45 minutes in the cooler end of this range; start to feel cold beyond this.
7mm (cold water): Tasmanian diving year-round, Victorian winter, SA in winter. Water below 14°C. The minimum for Tasmanian abalone diving. Consider a two-piece system (a 5mm farmer john plus a 5mm jacket) in Tasmanian waters for warmth and redundancy.
Freediving vs Snorkelling Construction
Freediving wetsuits are constructed differently from general-purpose suits. They are typically open-cell neoprene on the inside (which grips the skin directly for a better water seal and improved insulation) and closed-cell on the outside. They are more fragile than standard wetsuits, harder to get on (require lubricant — soapy water — for donning), and provide noticeably better performance at depth. Standard snorkelling suits are closed-cell inside and out: more durable, easier to put on, adequate for surface and shallow work.
Accessories That Matter
A wetsuit hood eliminates the largest single source of heat loss in cold water — the head. In Victorian and Tasmanian waters below 15°C, a 3mm hood makes more difference than adding 2mm to the suit thickness. Boots prevent foot discomfort on rocky entries and exits. Gloves in Tasmanian water allow extended diving time but reduce manual dexterity — abalone divers balance this trade-off constantly. Browse our water sports and diving accessories.
