You're standing in a surf shop, staring at a wall of wetsuits, and every single one has a different set of numbers on the tag. 2mm. 3/2mm. 4/3mm. You came in for one wetsuit and now you need a maths degree. Meanwhile, your kid is already bored and asking for ice cream.
Good news: picking the right wetsuit thickness for Australian waters is simpler than it looks. Let's break it down.
What Do the Numbers Actually Mean?
Wetsuit thickness is measured in millimetres, and the numbers tell you how thick the neoprene (or plant-based rubber) is in different parts of the suit. When you see a number like 3/2mm, that means:
- 3mm across the torso (chest, back, core) -- where your kid loses the most heat
- 2mm on the arms and legs -- thinner for flexibility so they can actually move
A single number like 2mm means the same thickness throughout the whole suit.
The thicker the material, the warmer the suit -- but also the stiffer and harder to get on. So you don't want to go thicker than necessary, unless you enjoy the wrestling match that is putting a rigid wetsuit on a wriggling seven-year-old.
The Three Thickness Options (and When to Use Them)
2mm -- The Warm Water Suit
Best for Queensland year-round, or anywhere in Australia during peak summer. A 2mm suit is lightweight, flexible, and easy to get on -- which honestly might be its biggest selling point. It provides enough insulation for water above 22 degrees and keeps the wind chill off between swims. Think of it as a step up from a rashie: real thermal protection without the bulk.
3/2mm -- The All-Rounder
Best for most of Australia from autumn through spring. If you're only buying one wetsuit, this is it.
A 3/2mm handles water between 16 and 22 degrees, which covers an enormous chunk of the Australian swimming calendar. Warm enough for Victorian spring, flexible enough for NSW autumn, and it won't turn your kid into a sweaty mess if the afternoon sun comes out. AVALY makes their steamers in 3/2mm Yulex plant-based rubber for exactly this reason -- it's the sweet spot for Australian conditions.
4/3mm -- The Cold Water Suit
Best for Victorian and Tasmanian winters, SA Gulf waters from June to August, or kids who run particularly cold. The trade-off is reduced flexibility and a longer getting-dressed battle, but when the water drops into the low teens, you'll be glad you went heavier. Most Australian kids won't need a 4/3mm unless they're swimming through winter south of Sydney.
State-by-State Thickness Guide
Water temperatures vary dramatically around Australia. Here's the breakdown by state and season.
| State / Region | Summer (Dec-Feb) | Autumn (Mar-May) | Winter (Jun-Aug) | Spring (Sep-Nov) |
|---|---|---|---|---|
| QLD (North) | 2mm or rashie | 2mm | 2mm | 2mm |
| QLD (South / Gold Coast) | 2mm | 2mm - 3/2mm | 3/2mm | 2mm - 3/2mm |
| NSW (North Coast) | 2mm | 2mm - 3/2mm | 3/2mm | 2mm - 3/2mm |
| NSW (Sydney) | 2mm | 3/2mm | 3/2mm | 3/2mm |
| VIC | 2mm - 3/2mm | 3/2mm | 3/2mm - 4/3mm | 3/2mm |
| SA | 2mm - 3/2mm | 3/2mm | 3/2mm - 4/3mm | 3/2mm |
| WA (North / Exmouth) | 2mm or rashie | 2mm | 2mm - 3/2mm | 2mm |
| WA (South / Margaret River) | 2mm - 3/2mm | 3/2mm | 3/2mm - 4/3mm | 3/2mm |
| TAS | 3/2mm | 3/2mm - 4/3mm | 4/3mm | 3/2mm - 4/3mm |
Seasonal Considerations Most Parents Miss
Autumn is sneaky. Ocean temperatures lag behind air temperatures by about six weeks. March and April are when parents get caught out -- it feels like summer, but the water has already started dropping. Wind chill matters more than water temp. A 21-degree day with an offshore breeze can make a 2mm suit feel inadequate fast. If your beach is windy, bump up a thickness. Morning vs afternoon is a real difference. If your child does surf lessons at 7am, go one step thicker than the table suggests. Dawn patrol is always colder than it looks.Springsuit or Steamer? How Thickness and Style Work Together
Thickness tells you how warm the suit is. Style tells you how much body it covers. You need both right.
- Springsuit (short arms, short legs) in 2mm: Warm water, maximum flexibility.
- Steamer (full arms, full legs) in 3/2mm: The workhorse. Covers the widest range of Australian conditions.
- Steamer in 4/3mm: Winter-grade warmth for cold southern waters.
AVALY's range is built around what Australian kids actually need: 2mm springsuits for the warm months and 3/2mm steamers for everything else, both made from Yulex plant-based rubber instead of petroleum-based neoprene. Two suits, and you're covered for just about every beach day on the calendar.
The One-Wetsuit Rule
If you can only buy one wetsuit and you live south of Brisbane, get a 3/2mm steamer. It handles the broadest range of conditions and works from late autumn through early summer.
If you live in Queensland, a 2mm springsuit will see you through most of the year.
Two wetsuits is ideal. But if budget says one, the 3/2mm steamer is the answer almost every time.
FAQs
Is a 2mm wetsuit warm enough for winter in Sydney?
Not for most kids. Sydney ocean temperatures drop to 17-18 degrees in winter, which puts you firmly in 3/2mm territory. A 2mm might work for a quick dip, but for anything over 20 minutes, your child will get cold. Save the 2mm for October onwards.
Can my kid wear a 3/2mm wetsuit in summer without overheating?
In water above 24 degrees, a 3/2mm can get uncomfortably warm during long sessions. For early morning swims or breezy days it's usually fine, but in peak summer heat, switch to the 2mm.
Does wetsuit thickness affect how easy it is to put on?
Absolutely. A 2mm suit goes on relatively easily. A 4/3mm requires patience, technique, and possibly bribery. Worth factoring in if your child dresses independently -- a suit they can get on themselves is a suit they'll actually wear.
How does Yulex compare to neoprene for warmth at the same thickness?
Identical. Yulex plant-based rubber provides the same insulation as neoprene at equivalent thicknesses. The difference is environmental -- Yulex produces up to 80% fewer CO2 emissions during manufacturing. Same warmth, smaller footprint.
My child always says they're not cold. Should I trust them?
No. Kids are famously unreliable narrators when it comes to body temperature, especially when getting out of the water is the alternative. Blue lips, shivering, goosebumps, or suddenly wanting to "just sit on the towel for a minute" -- if any of those appear, the suit is too thin or it's time to come in.
