How does a wetsuit actually work? From classic Neoprene to Yulex

A wetsuit is called a wetsuit because it is not meant to keep you completely dry. The goal is to trap a minuscule layer of water between the fabric and your skin. Your body warms this thin layer, and the suit insulates that warmth. So, one clear goal: keeping you warm in the lineup.

A brief history lesson: In the 1950s and 60s, surf legend Jack O'Neill was looking for a way to surf for longer than five minutes in the icy cold waters of San Francisco. He picked up neoprene material and designed the very first wetsuit. To this day, O'Neill is one of the absolute leaders in wetsuit tech.

The upgrade to 2026: Although we still commonly call it "neoprene," we now see that the best wetsuits are made from more sustainable alternatives. Think Yulex (natural rubber) or eco-foam made from oyster shells and recycled car tires. Less impact on the ocean, but with maximum stretch and insulation!

Single Lined vs. Double Lined: What's the difference?

Broadly speaking, there are two ways in which the rubber in wetsuits is finished:

• Single Lined (Smoothskin): This is the smooth, rubbery exterior you often see on the chest or back panel. The big advantage? It's wind and water-repellent. The icy cold North Sea wind slides right off, keeping your core warm. The disadvantage is that it's more vulnerable to tears from your fins or nails.
• Double Lined: This material has a flexible nylon or polyester lining on both sides (inside and out). It is incredibly durable, flexible, and comfortable. Today, we see incredible technologies in this, such as Rip Curl's super-fast drying Flashbomb linings or the thermo-linings from C-Skins and Vissla, which make your suit dry and warm in no time.

What thickness wetsuit do I need in the Netherlands?

The thickness of a wetsuit is always indicated in millimeters, adapted to the water temperature. You usually see two or three numbers (e.g., 4/3 or 5/4/3). The first, thickest number is for the rubber on your core (chest and back). The thinner numbers are for the arms and legs, so you maintain maximum paddling flexibility.

• Summer (July - Sept): 3/2 mm (or a shorty). Barefoot is fine!
• Spring / Autumn: 4/3 mm. Your absolute all-rounder. Sometimes 3mm booties are added if the North Sea is still/already chilly.
• Winter (Dec - March): 5/4 mm or 6/5 mm. This is the real deal. Cap, booties (5mm-7mm), and gloves are a must!

During deep winter sessions on the North Sea, you lose most heat through your head, hands, and feet. A wetsuit with an integrated cap (hooded wetsuit) is an absolute game-changer then, as it prevents flushing through the neck.

The perfect fit: Trying on suits

A wetsuit only works if it fits perfectly. Too big? Then cold water constantly flows through it, and you lose all your warmth. Too small? Then it constricts blood flow, and paddling feels incredibly heavy.

Sizes often work like clothing (XS to XL), but many brands also offer 'T' (Tall) or 'S' (Short) variants. An 'MT' (Medium Tall), for example, is perfect for someone with an M build but who is slightly taller than average.

Checklist: How do I know if it fits well?

• The "Factory Standard": A brand new suit should feel very tight in the store or at home. As soon as it gets wet, the material stretches slightly and molds to your body. So don't panic right away!
• Too small if... The neoprene on your shoulders 'shines' excessively (it's stretched tightly) or if it feels like your shoulders are constantly being pushed down.
• Too big if... You can easily grab the neoprene in a fold on your lower back, or if you have a lot of length or excess fabric at the wrists and ankles (you can easily stick your fingers between your neck and the fabric).

The Closure: Front Zip, Back Zip, or No Zip?

How you get into the suit largely determines flexibility and warmth. The zip is the main inlet for cold water.

1. Back Zip: The classic. Easy to get in and out. We see this a lot in entry-level models and summer suits. Disadvantages: the long zip reduces stretch in your back (making paddling harder) and lets in cold water more easily.
2. Chest Zip / Front Zip: The modern standard. You pull a flap over your head and zip it horizontally on your chest. This gives your back maximum freedom of movement and seals much better around the neck, letting in much less cold water.
3. Zip Free / Zip Less: The latest trend in the lineup. No stiff zips means 100% stretch and 0% water leakage through closures. Thanks to the extremely stretchy materials of 2026, you can now get into this just as easily as a chest zip.

The Seams (Stitching & Sealing)

Water can enter not only through the zip but also through the seams. The better the seam, the warmer the suit.

• Flatlock Stitch: The basic, flat seam. Lets water through. Ideal for breathable summer suits, but too cold for winter.
• GBS (Glued and Blind Stitched): The standard for warmer suits. The rubber is glued and half-thickness blind stitched, so no holes go all the way through the neoprene. The result? A waterproof, warm seam.
• Taped Seams: These are GBS seams, finished with flexible tape on the inside. This makes the seam even more waterproof, durable, and comfortable.
• Liquid / Sealed Seams: The ultimate defense against the cold. These are GBS seams where liquid rubber has been poured over the outside. Perfect for the hardcore winter surfer!

Ready for your new Wetsuit?

Still can't figure it out online? Come visit our surf shop on Vissershavenweg in Scheveningen. Our crew is ready with stoke, coffee, and a mountain of expertise to help you pull that perfect suit off the racks. See you in the water!