What Open Cell Wetsuits Are and Why Spearfishers Use Them
An open cell wetsuit has neoprene with the outer fabric layer removed, leaving the cell structure of the foam exposed on the inside. That exposed surface creates a suction seal against your skin, which traps a thinner layer of water than a closed-cell suit does. The result is better insulation in cold water and less bulk, which matters when you are moving through the water hunting.
Spearfishers choose open cell suits because they compress less under pressure than standard wetsuits. If you are diving to depth, a closed-cell suit gets thinner as the water pressure increases, and you lose warmth. An open cell suit resists that compression better, so you stay warmer on deeper dives. The trade-off is durability: the exposed neoprene tears more easily, and the suit requires more careful handling both in and out of the water.
Open cell suits are common in temperate and cold water spearfishing — places like California, the Northeast coast, and Europe. In tropical water where you need minimal protection, a closed-cell or spring suit is usually enough. In very cold water where you need serious insulation, some spearfishers layer an open cell suit under a closed-cell jacket for extra warmth.
Key Takeaways
- Open cell wetsuits seal directly to your skin and compress less under pressure, making them warmer than closed-cell suits at depth.
- The exposed neoprene on the inside surface tears easily, so you need to rinse and dry the suit carefully after every use.
- Open cell suits work best in water colder than 55°F, where the compression advantage and insulation matter most.
- Putting on an open cell suit requires a lubricant like soapy water to slide the suit over your skin without tearing the neoprene.
- Open cell suits typically cost 20 to 40 percent more than comparable closed-cell suits because the construction is more labour-intensive.
How the Seal Works and Why It Matters for Warmth
When you put on an open cell suit, the exposed neoprene on the inside adheres to your skin through suction. Your body warms a thin layer of water trapped between the neoprene and your skin — usually less than a millimetre thick. That small volume of warm water stays in place because the seal is so tight, and you lose very little heat to the surrounding cold water.
A closed-cell suit, by contrast, has a fabric layer between the neoprene and your skin. That fabric breaks the seal, so more water circulates inside the suit, and you have to warm a larger volume of it. In shallow water or short dives, the difference is small. But on a two-hour hunt in 50°F water, the open cell suit keeps you noticeably warmer because you are not constantly heating fresh cold water.
The compression advantage becomes real below 30 feet. At that depth, water pressure squeezes a closed-cell suit and reduces its thickness by 30 to 50 percent, depending on the suit's thickness and the depth. An open cell suit compresses less because the neoprene cells are already open and cannot be squeezed further. That means your insulation stays more consistent as you go deeper, which is why open cell suits are standard for deep spearfishing.
Putting On and Taking Off an Open Cell Suit
The biggest practical difference between open cell and closed-cell suits is how you dress. You cannot simply pull an open cell suit on like a closed-cell suit — the exposed neoprene will stick to your skin and tear. Instead, you need a lubricant to let the suit slide on smoothly. Most spearfishers use soapy water (a spray bottle with a few drops of dish soap mixed in) or a commercial wetsuit lubricant. Some use a plastic bag over each foot or arm to help the suit slide over.
The process takes longer than a closed-cell suit. Spray your body and the inside of the suit with the lubricant, then work the suit on slowly, starting with your legs. Once the suit is on, rinse off the excess lubricant with fresh water. When you come out of the water, rinse the suit immediately with fresh water — salt water and sun damage the exposed neoprene quickly. Hang it to dry in the shade, never in direct sunlight.
Taking the suit off requires the same care. Spray the inside with lubricant again, then peel it off slowly. If you rush, you will tear the neoprene. Some spearfishers keep their open cell suits in a mesh bag and rinse them in the bag to reduce the risk of snagging the material on zippers or rough surfaces.
Durability and Maintenance
Open cell neoprene is softer and more delicate than the fabric-backed neoprene in a closed-cell suit. Small tears in the exposed surface can grow quickly if you do not repair them. A pinhole leak will not sink you, but it will let water circulate inside the suit and reduce warmth. Most spearfishers carry a small repair kit — neoprene cement and patches — and fix small tears the same day they happen.
Sun damage is the other major threat. Ultraviolet light breaks down neoprene, and the exposed surface of an open cell suit is more vulnerable than a closed-cell suit. Always dry your suit in the shade, and store it in a cool, dark place. If you leave an open cell suit in the sun for a few hours, the neoprene becomes brittle and loses elasticity.
Salt water and chlorine both degrade neoprene over time. Rinse your suit with fresh water immediately after every use, and rinse it again before you store it. If you fish in chlorinated pools or brackish water, rinse more thoroughly. A well-maintained open cell suit lasts three to five years with regular use. A neglected one can fail in a season.
Thickness, Temperature Rating, and Choosing the Right Suit
Open cell suits come in thicknesses from 3mm to 7mm, and sometimes thicker for extreme cold. A 3mm suit works in water from 60 to 70°F. A 5mm suit is good from 50 to 60°F. A 7mm suit handles water below 50°F. These are guidelines, not rules — your personal cold tolerance, how active you are during the dive, and how long you stay in the water all matter.
Some manufacturers rate their suits by water temperature rather than thickness. Read the rating carefully: a suit rated for "50 to 60°F" is designed for that range, but you may need a thicker suit if you are sensitive to cold or plan to stay in the water for hours. Many spearfishers buy a 5mm open cell suit as their main suit because it covers the widest range of conditions.
Fit is critical. An open cell suit that is too loose will let water circulate inside, defeating the purpose of the seal. An open cell suit that is too tight restricts movement and can tear when you bend or reach. Most manufacturers provide sizing charts based on height and weight. Order from a retailer that accepts returns, because fit varies between brands.
Open Cell vs. Closed-Cell and Hybrid Options
A closed-cell suit is more durable, easier to put on, and cheaper. It works well in water warmer than 55°F or for short dives where compression is not a major factor. If you are starting out or fish mostly in mild water, a closed-cell suit is the practical choice. You can always upgrade to open cell later.
Some spearfishers use both. They wear a closed-cell suit as a base layer and pull an open cell jacket or vest over it for extra warmth in very cold water. This hybrid approach gives you the compression advantage of open cell where you need it most — the core — while keeping the durability and ease of a closed-cell suit for your arms and legs. It costs more upfront but extends the range of conditions you can fish comfortably.
A few manufacturers make semi-open-cell suits, where only the chest and back are open cell and the arms and legs are closed-cell. These are a middle ground: warmer than full closed-cell, more durable than full open-cell, and easier to put on than a full open-cell suit. They cost more than either option alone, but some spearfishers find the trade-off worth it.
Cost and Long-Term Value
Open cell wetsuits typically cost between $200 and $500, depending on thickness, brand, and whether it is a custom fit. A comparable closed-cell suit costs $120 to $300. The open cell suit costs more because the construction is more labour-intensive and the materials are more expensive.
The value depends on how much you fish and in what conditions. If you hunt in cold water regularly, the warmth advantage of an open cell suit means you stay comfortable longer and can fish more days per year. If you fish occasionally in mild water, a closed-cell suit will serve you fine and save you money. If you are serious about spearfishing in temperate or cold water, an open cell suit is worth the investment because it performs better and lasts several years with proper care.
Frequently Asked Questions
Can I wear an open cell suit in warm water?
Yes, but it is not ideal. In water warmer than 70°F, you do not need the insulation, and the suit will feel restrictive. A thinner closed-cell suit or a rash guard is more comfortable. If you already own an open cell suit and want to use it in warm water, a 3mm open cell is the thinnest option, but you will still be warmer than necessary.
What happens if I tear my open cell suit underwater?
A small tear will let water in, but it will not cause the suit to fail immediately. You will feel cold water circulating inside, and your warmth will drop. If the tear is large, you may want to end the dive. Small tears can be repaired with neoprene cement and patches once you are back on shore. Carry a repair kit if you dive regularly in open cell.
Do I need special gloves and a hood for an open cell suit?
No, but open cell gloves and hoods work better with an open cell suit because they seal the same way. A closed-cell glove or hood will work, but you will lose some warmth at the wrists and neck. Many spearfishers use open cell gloves and a closed-cell hood, or vice versa, depending on which areas get cold fastest.
How long does it take to put on an open cell suit?
With practice, five to ten minutes. Your first few times may take longer as you learn to work the lubricant and avoid tearing the neoprene. Once you develop a routine, it becomes faster. Some spearfishers keep their suit on a hanger and spray it with lubricant before each dive to speed up the process.
Can I machine wash an open cell suit?
No. Machine washing will tear the exposed neoprene and damage the suit. Always rinse by hand with fresh water, gently rubbing away salt and debris. Hang to dry in the shade. If the suit is very dirty, soak it in fresh water for a few minutes before rinsing, but do not scrub or wring it out.