What wetsuit thickness to choose for a child: 3/2mm or 4/3mm?

Choosing the thickness of a wetsuit is one of the most important criteria for keeping a child warm, motivated, and safe in the water.
For a parent, understanding the difference between 3/2mm and 4/3mm helps avoid comfort mistakes… and wasted money.

At ONE SURFING CO., we equip young surfers with Japanese neoprene, the warmest and most flexible in the world. Here's how to choose the right thickness based on the season and water temperature.

The difference between 3/2mm and 4/3mm (simple and quick)

A wetsuit:

• 3/2mm → 3mm on the torso, 2mm on the arms & legs

• 4/3mm → 4mm on the torso, 3mm on the arms & legs

💡 The greater the thickness → the higher the warmth
But → flexibility slightly decreases (except with Yamamoto neoprene).

When to choose a 3/2mm wetsuit for a child?

The 3/2mm is ideal for:
✔️ water temperatures between 14°C and 20°C
✔️ spring, summer, and early autumn
✔️ short or moderate sessions even in winter
✔️ Hossegor conditions from April to October

Advantages of a 3/2mm

• Very flexible → perfect for movements

• Easy to put on: important for children

• Lighter → more comfort
  

When to choose a 4/3mm wetsuit for a child?

The 4/3mm is the perfect choice for:
✔️ waters between 10°C and 15°C
✔️ late autumn, winter, cold spring
✔️ children who get cold easily
✔️ longer sessions

Advantages of a 4/3mm

• Enhanced warmth

• Better insulation in cold water
  

• Ideal for motivated children who surf all year round

And with Japanese neoprene, the difference is even more pronounced

The Japanese neoprene we use:
✔️ is naturally warmer
✔️ floats better (reassuring for children)
✔️ absorbs only 2% water
✔️ dries faster
✔️ retains its flexibility longer

👉 A 3/2mm is as warm as a classic 4/3mm.
👉 A 4/3mm is equivalent to some 5/4mm from other brands.

What thickness according to water temperature? (SEO table)

How to tell if your child is cold?

Signs to look out for

• blue lips

• shivering

• difficulty paddling

• decrease in energy

• desire to stop quickly

If any of these signs appear → the wetsuit is not thick enough.

Parents' #1 mistake: buying too big

Many think:
👉 "I'll get a size up, it will last longer".

❌ False.
A wetsuit that is too big lets water in → the child gets cold → they stop surfing.

💡 Hence the benefit of the ONE SURFING CO. subscription.
The size follows growth at no extra cost.

Conclusion: what is the best thickness?

Simple answer:

• 3/2mm → for waters between 14–20°C

• 4/3mm → for waters between 10–15°C

• In Japanese neoprene → one thickness is as warm as the next category up

• For a growing child → prefer a flexible system (subscription)

The essential thing: keep the child warm so they progress and enjoy themselves.

Give your child the right thickness — and the right size, all year round.

👉 Discover the children's subscription here.
👉 See our 3/2mm and 4/3mm wetsuits here.
👉 Why choose Japanese neoprene? Learn more here.

FAQ

1. What wetsuit thickness for a child?
3/2mm for warm/moderate water, 4/3mm for cold water. With Yamamoto, the warmth is superior.

2. Is a 4/3mm too warm?
Not for children who get cold easily or for waters below 16°C.

3. Does thickness affect mobility?
Slightly, except with Japanese neoprene where flexibility is very high.

4. Do you need a different wetsuit in winter and summer?
Yes, unless you have a subscription and can alternate.