All neoprene is the same right? Just some are thicker than others? Nope...
The formula for modern neoprene has been tinkered and tweaked by so many manufacturers today and not all neoprene is made the same. Like so many things in life today everybody has their own secret recipe and each is specialised for a certain task.
Neoprene dates back to the 1930's and originally marketed as 'DuPrene' but this was very different to what we would recognise as neoprene. In the early '50s an American physicist considered the benefit of air filled rubber material layers as an insulating suit. With the thousands of tiny bubbles trapped inside these would act as insulation, a lot like double glazing, slowing heat transfer and the idea was pitched to the Navy but it never stuck as the Navy believed the bubbles in the suit would be detectable by radar.
Later Jack O'Neill pioneered the closed cell neoprene wetsuit and marketed it to surfers, soon followed by Body Glove and other manufacturers. But this sponge rubber material had its drawbacks. Before lined neoprene was produced the raw foam rubber sheets where quite fragile and tricky to don and doff as the suits weren't tailored as well as they are today and the seams would tear if you were too rough.
Nylon linings made wetsuits easier to put on but made the suit less flexible and rigid as a trade-off. Reversed strips were placed around the neck and cuffs so the smooth rubber would create a more effective seal to slow water ingress.
The second outer lining that added colour and flare to wetsuits arrived in the '60s but didn't become popular until the '70's. This double lined neoprene greatly increased a wetsuits abrasion and tear resistance and made you stand out on the dive site.
Early suits were simply sewn together which would easily rip so seam taping began to appear in the '60s. By gluing a strip of material over the seams you would spread the stress of pulling a suit on and make the suit more comfortable to wear. Later glued seams and blindstitch, which doesn't penetrate all the way through the material, would reduce water ingress and increase strength of the seams.
Today's neoprene is stronger, more flexible, friendlier to the environment, crush resistant and hypoallergenic. Many wetsuits are made from limestone now and other materials compared to the petroleum based older suits. Wetsuits have split into a few different specialities also such as Surfing, Freediving and Scuba diving.
While Surfing suits are flexible they tend to compress more at depth making them unsuitable for diving. They're made to keep you warm on the surface and let you move around all the time so while they may appeal and feel nice once on, once you get down you can chill pretty fast.
Freediving suits have stuck with the two-part open cell design, though harder to put on they can keep you warmer in the water submerged for long periods. Two-part open cell suits are great at keeping you warm when you're in the water for long periods but you require lubricants and a lot of patience to get into one properly.
Scuba Divers need a suit that lets you move, doesn't compress and is easy to don and doff. Scuba wetsuits are the best mix of these traits and you're always trading flexibility for warmth and compression. Wearing a surfing suit whilst diving will get you cold much faster and a freediving suit will take you longer to put on and take off than necessary so stick to a scuba suit, it's what they're made for and a lot of research goes into them.
Modern suit design focuses on the cut and the lining to make them more efficient. Computer assisted design and water jet cutting allow for fewer seams and more efficient tailoring of each suit. You can find cheap budget suits almost anywhere now but you can feel the drop in quality when you first touch it and especially when you dive it.
Budget neoprene is often petroleum based with a thin lining that many people react to and it will both compress and stiffen quickly so the old adage Buy Cheap, Buy Twice applies. If you want a wetsuit that will last and keep you warm then it's best to save your money and buy a more expensive suit, it will last longer and keep you warmer. A decent suit will last a good 5-10+ years if you look after it but all wetsuits will compress over time so your 10 year old 5mm suit is probably a 3mm now.
Neoprene such as Scubapro's X-Foam is one of the greenest compounds available. Made from limestone X-Foam has moved away from the usual petroleum based formula and conforms to strict PAH requirements. Even the glue used to bind the panels together is solvent free and water-based making it better for divers and the environment and reduces the amount of glue required for each suit.
Similar to X-Foam Yamamoto #38 is also made from limestone with a honeycomb bubble pattern that keeps the strength and flexibility high as well as the warmth. The honeycomb and closed cell structure reduces weight, high heat retention, good flexibility and high resistance to water pressure.
Modern suits have an internal lining that's soft and flexible making them easy to don and doff but on their higher end ranges you'll find panels of warmer linings such as Fourth Element's Hexacore and Thermoflex, Scubapro's DiamondSpan or Seac's Thermal Fibre Plush linings.
These plush linings trap water movement inside the suit so that cold water doesn't flow around inside the suit so you'll find after the dive when you take the suit off plenty of warm water will flow out that you didn't know was there.
Many of these linings are quick drying too between dives so you don't have to squeeze into a cold soggy suit for your second dive, just remember to hang it inside out...
There are four basic seals on a wetsuit, the first and cheapest is a simple roll. The edge of raw neoprene can be quite fragile so manufacturers fold edges over and sew it together so you have a rounded edge but it doesn't create a great seal to stop water and it isn't very flexible. Some suits have rolled glideskin at the very edge of the cuff which is more effective but not the best.
The Canadian seal is a ring of glideskin inside the sleeve either right at the cuff or further up the sleeve. You see this mainly in gloves but some suits have it too and they are effective because the water has already slowed down to get under the sleeve before it hits the seal.
A glideskin lining is much the same as the Canadian seal but the whole internal lining of the cuff is a smooth lining that bonds to the skin when wet. Some suits will have the glideskin facing outwards and a cover over that so your gloves can be layered up and seal against the glideskin.
So Which is the Best Wetsuit?
Unfortunately, that depends on you and your needs. As soon as you pick up an expensive suit and a cheap suit you'll know why one is more expensive and there is another handy hint that compares how warm a suit is before you jump in the water.
Most wetsuits, but not all, will have a thermal protection class on the label with Class A being the best. The better the fit, material, seals and flush-defeat the higher the class and warmer the suit will be. The fit is everything though. You can have the thickest, warmest wetsuit with all the best seals and stitching but if it doesn't fit then you will get cold. Too tight and you can restrict blood flow, too big and cold water will just flush in and out of the suit so you have to get the right suit.
Not all wetsuits will be rated though, shorties don't classify as exposure protection so they won't have a class but you'll usually find an A, B, C or D inside your suit. Hoods and Gloves will also make a big difference to how warm you will be in the water.
For a dive holiday where you'll be hoping in and out of your suit often you'll want something like the Fourth Element Xenos or AquaLung AquaFlex because they're made to be flexible and easy to don and doff.
For some divers the best wetsuit may not even be a wetsuit; there are a few wetsuit alternatives out there that have a few benefits over neoprene. These alternatives are neutrally buoyant so you don't need to add any lead to sink, they come in two parts to make donning easier and they dry pretty fast but they do equate to a 2 or 3mm suit so they're not the warmest.