Skip to content

Dry suits

A dry suit is what separates a cold-water diver from a comfortable cold-water diver. Unlike wetsuits, a dry suit seals you off from the water completely, keeping you dry throughout the dive. Combined with the right undersuit, it allows you to dive in near-freezing temperatures and stay in the water far longer than any wetsuit would permit. Whether you dive wrecks, caves, or open water in cold conditions — a dry suit is not a luxury, it is core equipment.

How Dry Suits Work

A dry suit creates a watertight barrier between the diver and the surrounding water using sealed wrist and neck seals and a waterproof zipper. The suit itself provides little to no thermal insulation in most designs — the warmth comes from the air layer trapped inside and from the undersuit worn beneath it.

During descent, the air inside the suit compresses. To prevent squeeze and maintain comfort, the diver adds air through an inflator valve, typically connected to a low-pressure hose from the first stage regulator. On ascent, expanding air is vented through an exhaust valve, usually located on the upper left arm. Managing this air is a fundamental drysuit diving skill — it directly affects buoyancy, trim, and comfort.

Dry Suit Materials

The two main categories of drysuit construction are membrane (trilaminate) and neoprene, and the choice between them shapes the entire diving experience.

Trilaminate (membrane) suits are built from three bonded layers — typically a waterproof membrane sandwiched between a durable outer fabric (often nylon or Cordura) and a comfortable inner lining. They offer no inherent insulation, so all warmth comes from the undersuit. The upside is versatility — you can adjust your thermal protection by swapping undersuits for different water temperatures. Trilaminate suits are lighter, dry faster, and pack smaller for travel. They are a popular choice in technical diving for their freedom of movement.

Neoprene suits — including standard neoprene and crushed (compressed) neoprene — provide built-in thermal insulation from the material itself. Standard neoprene offers the most warmth but compresses at depth, which changes both insulation and buoyancy. Crushed neoprene minimises this compression effect while retaining much of the durability neoprene is known for. Neoprene suits tend to be heavier, take longer to dry, but are exceptionally tough — a common choice for wreck diving where abrasion resistance matters.

Dry Suit Categories

Dry Suits with Front Zipper

Front-entry suits allow the diver to don and doff the suit independently, without assistance. The zipper runs across the chest or torso, making self-sufficiency on the dive site straightforward.

Dry Suits with Back Zipper

Back-entry suits use a zipper across the upper back or shoulders. They often provide a flatter front profile but typically require a buddy to close and open the zipper.

Undersuits

The insulation layer worn beneath the dry suit. The undersuit is what actually keeps you warm — from thin base layers for temperate water to thick Thinsulate-lined suits for ice diving.

Boots

Drysuit boots — either integrated into the suit or worn separately — protect your feet and provide grip on slippery surfaces. Rock boots with rigid soles are common for shore entries over rough terrain.

Undersuit Socks

Thermal socks designed to be worn inside drysuit boots or integrated socks. They add insulation to the feet — often the first part of the body to get cold on longer dives.

Belts for Dry Suits

Crotch straps, waist belts, and accessory belts designed to manage suit fit and prevent air migration. A well-placed belt keeps the suit snug and reduces ballooning in the legs.

Replacement Parts

Seals, zippers, valves, and other components that wear over time and need periodic replacement. Maintaining these parts is essential for keeping the suit watertight and functional.

Accessories

Additional items that complement a drysuit setup — from seal lubricants and talc to dry glove systems, P-valves, and repair kits.

What to Look for in a Dry Suit

  • Material and construction — trilaminate for versatility, lighter weight, and faster drying; neoprene or crushed neoprene for built-in warmth and abrasion resistance. The choice depends on your typical diving environment and how much you travel with your gear.
  • Zipper placement — front-entry zippers allow independent donning and doffing; back-entry zippers may offer a cleaner profile but require assistance. Consider how and where you dive.
  • Seal type — latex seals offer a precise, adjustable fit and are easy to replace. Silicone seals provide similar flexibility and suit divers with latex allergies. Neoprene seals are more durable but stretch over time and can be harder to get a tight seal.
  • Fit — a drysuit must allow full range of motion: reaching your back-mounted valve, bending your knees for finning, squatting for shore entries. Too tight restricts movement; too loose creates excess air pockets that complicate buoyancy control.
  • Valve quality — the inflator and exhaust valves are critical components. They must operate smoothly, reliably, and be compatible with your regulator setup.

Maintenance and Care

After every dive, rinse the suit thoroughly with fresh water — inside and out if it has been flooded. Pay special attention to the zipper: rinse it, dry it, and lubricate it regularly with manufacturer-recommended wax or lubricant. A neglected zipper is the most common reason drysuits fail.

Store the suit hanging in a cool, dry place out of direct sunlight. UV exposure degrades both latex seals and neoprene over time. Avoid folding the suit for extended periods — this can crease and weaken the material, especially on trilaminate suits.

Latex and silicone seals should be inspected before each dive for cracks, tears, or loss of elasticity. Seals are consumable components — they will eventually need replacement. Keep spare seals and a seal replacement kit in your dive bag for trips. A torn neck seal at a remote dive site will end your diving unless you can fix it in the field.

Schedule a professional pressure test and service at least once a year, or whenever you suspect a slow leak. Valves, seams, and zippers all benefit from periodic professional inspection.

Frequently Asked Questions

What is the difference between a trilaminate and a neoprene dry suit?

A trilaminate suit is a membrane construction that provides no inherent insulation — all warmth comes from the undersuit. It is lighter, dries faster, and allows easy thermal adjustment by changing the undersuit. A neoprene suit has built-in insulation from the material itself, is more abrasion-resistant, but is heavier, takes longer to dry, and offers less flexibility in thermal layering.

Front zipper or back zipper — which is better?

Neither is objectively better — it depends on how you dive. A front zipper lets you get in and out of the suit without help, which is a significant advantage if you dive without a regular buddy or from shore. A back zipper can provide a cleaner front profile but almost always requires assistance to close.

How long do drysuit seals last?

Latex seals typically last 2–5 years depending on frequency of use, UV exposure, and care. Silicone seals tend to last longer but are more prone to tearing if snagged. Neoprene seals are the most durable but lose their tight fit over time as the material stretches. Regular inspection and timely replacement are key.

Do I need a special undersuit, or can I wear regular thermal clothing?

You can wear regular thermals for mild conditions, but purpose-built undersuits perform significantly better. They are designed to maintain loft and insulation even when compressed at depth, wick moisture effectively, and fit under a drysuit without bunching or restricting movement. For cold water diving, a dedicated undersuit is a worthwhile investment.

How do I take care of a drysuit zipper?

Rinse the zipper with fresh water after every dive, allow it to dry, and apply the wax or lubricant recommended by the manufacturer. Never force a stiff zipper — if it resists, it probably needs cleaning and lubrication. Store the suit with the zipper slightly open to relieve tension on the teeth. A well-maintained zipper can last the lifetime of the suit; a neglected one can fail within a season.

Close