Wetsuit Thickness Explained: What You Need & When
Choosing the right wetsuit thickness can make or break your time in the water. Whether you’re surfing in Cornwall, wild swimming in chilly lakes, or chasing waves abroad, getting the right balance of warmth and flexibility is key. Here's your go-to guide to wetsuit thickness—what it means, when to wear what, and how to choose the best fit for your adventure.
What Does Wetsuit Thickness Mean?
Wetsuit thickness is measured in millimetres and is usually shown as two or three numbers, like 5/4mm or 3/2mm. These numbers refer to the thickness of the neoprene in different areas of the suit:
• The first number is the thickness over your core (torso) for warmth.
• The second number is the thickness in the arms and legs for flexibility.
• Some suits include a third number for even thinner panels, often behind the knees or at the elbows.
Wetsuit Thickness Guide by Water Temperature
Tip: If you feel the cold more than most, go thicker. If you prioritise flexibility and you're moving a lot, go thinner.
Wetsuit Styles & When to Wear Them
Shorty (2mm): Great for hot summer days, tropical holidays or quick dips.
Full Suit (3/2mm or 4/3mm): Your go-to for UK spring and autumn. Keeps you warm without sacrificing too much movement.
Winter Suit (5/4mm+): Designed for cold water surfing. Add boots, gloves and a hood for full protection.
Key Considerations When Choosing a Wetsuit
• Location: UK waters are cold most of the year, so plan accordingly.
• Season: Always think about when and where you’ll be in the water.
• Your Tolerance to Cold: Some people run hot, some don’t. Don’t suffer—go thicker if needed.
• Activity Level: High-intensity surfing warms you up faster than a chilled-out SUP cruise or swim.
Final Word
Wetsuit thickness might seem confusing at first, but once you know your season, your sport and your cold tolerance, you’ll find the perfect fit. Explore our full range of men’s, women’s and kids’ wetsuits to find your match for every season and every session.
We have a wide range of suits – from trusted brands like O’Neill, C-Skins, Rip Curl and more.
Frequently Asked Questions
Which thickness wetsuit should I get as an all-rounder?
We'd suggest a 4:3 as it's slightly thicker than a summer suit so will keep you in the water for longer throughout the autumn and spring.
I'm coming to Cornwall in summer. Which wetsuit should I get?
A 3:2 Wetsuit Thickness is ideal for Cornwall in the summer.
Which thickness should I get for swimming?
Wetsuits are very buoyant so the thinner the better for swimming so it's not super floaty.
Which wetsuit thickness for paddleboarding?
It depends how much you fall in! But generally would recommend a 3:2 or 4:3 over a 5:4 so you have better flexibility for paddling.
