There’s more to it than just choosing a thickness and a color. Our consumer’s guide to neoprene shows you the difference between the good. the bad and the downright cheap.

How Does a Wetsuit Work?

Wetsuits keep you warm in two ways: One is by insulating against the direct conduction of heat from skin to water to neoprene to ocean. The insulation is entirely in the bubbles of nitrogen trapped within the neoprene, not the neoprene itself, which is merely a framework to position thousands of bubbles close to your skin.

The second way wetsuits work is by stopping the flow of cold water along your skin, which would cool you by convection. When water flushes through your wetsuit, it loads up with your body heat and dumps it into the ocean.

Convection losses may be even more serious than conduction losses. Certainly, sailors have survived in cold water for surprisingly long times clothed only in pants and jackets, which prevented convection but not conduction. So, low flow in your wetsuit, which is a result of a good fit, may be even more important than thickness.

What Style Should I Buy?

Opt for full coverage. Shorties have their uses, but if you leave your arms and legs unprotected, you need more rubber over your torso to make up for it. If you cover your entire body (including your head), you’ll probably need less total neoprene and have to put less weight on your belt. A thinner full suit may well be able to provide as much warmth as a thicker shorty. Besides, you should give your arms and legs protection from sun and scrapes.

How to buy a wetsuit

Full Suit or Farmer John/Jane?

The two-piece farmer john or jane used to be the standard wetsuit, but today many divers prefer the one-piece suit, called a full suit, jumpsuit or steamer. The biggest reason is versatility. The full suit can be combined with a vest or jacket to give two layers of insulation over the torso, like the two-piece, or it can be worn alone in warmer water for more flexibility and less buoyancy.

Two-piece suits still have one advantage, however. Divers with odd leg-to-torso proportions may get a better fit with a two-piece suit because they can mix and match the sizes. Some companies offer jumpsuit sizing with optional long or short legs to solve this problem, but most do not.

What About the New “Semi-Dry” Suits?

No wetsuit or “semi-dry” suit will keep you completely dry. Your sweat, if not the seawater, will make your skin wet, which unfortunately accelerates the cooling process. (Water conducts heat from your body much more quickly than air.) What semi-dry suits can do is reduce the “flushing” effect, the amount of cold water that enters and displaces warm water. This convection loss of heat may be even more important than the direct conduction loss through the insulation.

The best fitting suit is a made-to-measure custom wetsuit that fits you exactly. But these can be expensive. In recent years, wetsuit designers have paid more attention to the water entry points: the wrists, ankles, neck and zippers. If they can be sealed, so the theory goes, a close fit is not as critical and the off-the-rack mass-produced suit can be as warm as the custom suit. That’s true to a point, but be aware that any substantial pocket of loose neoprene will act as a powerful pump whenever you move and will suck water past the best seals. Look for effective seals by all means, especially at the neck and the zippers, but do not expect them to compensate for a poor fit.

How Thick?

You can find charts (see “Exposure Suit Comfort Zones”) to tell you what thickness of neoprene is right for what temperature, but in fact individuals differ enormously in how quickly they lose heat. Thin people, older people and women tend to chill sooner, but generalizations are almost impossible to make, and apparently similar divers will differ widely. In fact, your body’s insulation needs will differ from one day to the next depending on the state of your rest, nutrition and health.

Your wetsuit needs will also differ with the depth of the dive. In fact, depth may well be more important than water temperature in deciding how thick your wetsuit should be. That’s because neoprene compresses with depth, and the thinner it is, the less insulation it can offer. Some neoprenes compress more than others, but typical neoprenes lose half their insulation value at 60 feet.

Can You Buy Just One Wetsuit? You can if you follow these two guidelines:

* Thicker is better. You can always open a zipper if the wetsuit is too warm. While you sacrifice mobility with a thicker wetsuit, that’s only an inconvenience. Hypothermia is misery and can be life-threatening. That doesn’t mean you should take a 7mm wetsuit to Cozumel, but for diving outside the tropics you should probably buy the thickest suit that fits your needs for your coldest diving. There are divers who can get by with a 5mm suit in New England, but they’re the lucky few.

* Plan on layering. Adding a vest, a jacket or both and switching to thicker boots, gloves and hood lets you match thickness to conditions. Don’t plan to buy a single piece of rubber; you need a wardrobe.

How Much Should You Spend?

The recent popularity of dry suits has put downward pressure on wetsuit prices and spurred their technical improvement, proving again Dr. Johnson’s dictum that the prospect of extinction “wonderfully concentrates the mind.” While there are overpriced wetsuits, most of them – especially those from the companies that specialize in wetsuits – are competitively priced.

But that does not mean the $149 wetsuit is the bargain it looks. The corner that is cut most often is the quality of the neoprene. Inexpensive neoprene is often “cut” with non-functional fillers like clay. It may feel good in the store and may be warm for the first few dives, but it will probably compress quickly at depth and not be as warm. Even worse, it will probably crush permanently after only a few deep dives. Cheap neoprenes are often given their softness by incomplete curing, so the molecular links are not fully made. It’s like a “half-cooked pancake,” as a Rubatex engineer put it. The incomplete links break down under pressure, the gas bubbles collapse and the neoprene loses its insulation.

How Can I Tell Good Neoprene From Bad?

Unfortunately it’s not easy. Neoprene varies widely in its ability to insulate and, even more, in its ability to keep insulating over time and at depth. Some goes flat in a few dives, some lasts for years.

Most of it sold in the U.S. comes from DuPont in the form of pellets. A dozen or more foam makers like Sheico in Taiwan, Yamamoto in Japan and Rubatex in the U.S. add various chemicals, then add the bubbles, form it into sheets and glue on the nylon, or plush lining. Each company makes half a dozen or so grades of neoprene, with different properties.

Unfortunately, it’s difficult to tell which grade of whose neoprene is in a given suit. Labels don’t say and even the wetsuit suppliers (some of whom do not make the suits themselves) often don’t know much about the neoprene. Your retailer probably knows less. You’re on your own. Try these tests:

* Squeeze it. Good neoprene should resist squeezing, and should “snap back, not crawl back” when you release it, as one engineer expresses it. The difference is not obvious until you compare several wetsuits side by side. Try folding a sleeve over so you can pinch four layers at once.

* Stretch it. The better the neoprene stretches, the better it will conform to your body and the fewer hollows will result to pump water. But be careful here: the neoprene that stretches is often the neoprene that squeezes, too. Some premium neoprenes have stretch without squish, but cheaper ones do not.

Typically, neoprene will stretch in one direction more than another. It’s not the neoprene, it’s the nylon bonded to it that’s restricting stretch in one direction. Ideally, the suit should be cut so the maximum stretch is around the diameter of the arms, legs and torso, not down their lengths.

* Weigh it. Or heft it to guess its weight. Generally, a heavier wetsuit is better. The walls of its bubbles are probably thicker and stronger and will stand up to compression better.


  • LOOK for a wetsuit that offers full body coverage.
  • CHOOSE a style – one piece or two – that is appropriate for your needs.
  • GET the best fit possible so that your wetsuit minimizes the amount of water that enters the suit but doesn’t constrict your circulation.
  • CHECK water entry points – wrists, ankles, neck, zippers – to ensure a tight seal.
  • SELECT a thickness based on the kind of diving you plan to do, but remember that if you’re too warm, you can always open a zipper.
  • BUY additional pieces – vest, boots, gloves, hood – that will allow you to customize coverage according to diving conditions.
  • EXAMINE the neoprene closely to determine its quality. Will it insulate well and keep insulating well?

How Tight Is Too Tight?

Tighter is better, up to a point. Zip it up and take a deep breath. Are you fighting the neoprene to expand your chest? Can you touch your toes? Wear the suit for five minutes or so. Does your face turn red? Are the veins standing out on the backs of your hands and feet?

Ideally, a wetsuit should touch you everywhere without stretching too much. Fighting to get the suit to stretch wastes energy, and stretched neoprene is thinner.

Exposure Suit Comfort Zones

water temp

75-85F 1/16[inches] (1.6mm) neoprene, Lycra, Polartec

70-85F 1/8[inches] (3mm) neoprene

65-75F 3/16[inches] (5mm) neoprene

50-70F 1/4[inches] (6.5mm) neoprene

35-65F 3/8[inches] (9.5mm) neoprene, dry suit


Sure you hate wearing a hood. Everybody does. But it’s the most important piece of neoprene you can wear, inch for inch.

The reason lies in how your body reacts to cold. It constricts the blood vessels near your skin, so your blood won’t become chilled. That’s why your skin looks white and your fingers don’t work very well – they’ve been starved of blood. In a sense, your body is withdrawing into its core and using its outer layers as an exposure suit.

But it can’t withdraw blood from your head because your brain needs a constant supply. Your carotid arteries continue at full bore and the rest of your head’s circulation system, most of which lies just under your scalp, continues pumping oxygen – and heat – at full speed. Blood, now cooled, returns to your body core and cools it too. The result is that even a naked diver will lose about 40 percent of his body heat through his head.

So wear a hood. Serious claustrophobes can enlarge the face opening. Thin hoods and hooded vests are also available and will work well without the restrictions of a thick hood. Even a bathing cap is better than nothing.

Nearly all recreational wetsuits use medium grades that are a good compromise between performance and cost. When I recently referred to the neoprene in a Dacor wetsuit as “medium quality,” some readers interpreted that as a criticism, but actually it was a compliment. Neoprenes used in recreational wetsuits from reputable makers do vary somewhat, but nearly all lie within the range of “medium” quality, which is, for our purposes, good neoprene.


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