The choice between a wetsuit and a drysuit comes down to water temperature, dive duration, and how much you're willing to invest in thermal protection. Both keep you warm underwater, but they work on completely different principles and require different skills to dive.
How Wetsuits Work
A wetsuit traps a thin layer of water between your skin and the neoprene. Your body heats this water, and the neoprene insulates to prevent it from being flushed away by surrounding cold water. The thicker the neoprene, the better the insulation — but also the more buoyant, the more restrictive, and the more weight you need to compensate.
Wetsuits compress at depth, losing thickness and therefore insulation. A 7mm suit at 100 feet may only provide the insulation of a 3mm suit due to compression. This means you get progressively colder as you go deeper.
How Drysuits Work
A drysuit seals completely — neck, wrists, and zipper — keeping you dry inside. Insulation comes from the undergarment you wear beneath the suit and a layer of air (or argon) between you and the suit shell. Because the insulating layer is air or gas rather than compressed neoprene, a drysuit maintains its thermal performance at depth.
Drysuits add a second buoyancy control mechanism. You must manage air in the suit (via an inflate valve and dump valve) alongside your BCD, which adds complexity. Most divers take a drysuit specialty course to learn these skills.
Side-by-Side
| Factor | Wetsuit | Drysuit |
|---|---|---|
| Water temp range | 50°F+ (with 7mm) | Any temperature |
| Insulation at depth | Degrades (neoprene compresses) | Maintained (gas layer) |
| Buoyancy management | BCD only | BCD + suit inflation |
| Training required | None beyond basic cert | Drysuit specialty recommended |
| Cost | $ to $$ | $$$ to $$$$ |
| Weight & bulk | Moderate | Heavier, bulkier |
| Travel-friendly | Yes (rolls up) | No (bulky, fragile seals) |
| Comfort at surface | Cold when wet and windy | Warm and dry |
When to Choose Each
Choose a wetsuit if you dive primarily in warm to moderate water (above 60°F), travel frequently, prefer simplicity, and want lower cost. A 5mm wetsuit covers most temperate diving, and a 3mm suit handles the tropics.
Choose a drysuit if you dive regularly in water below 60°F, make long or deep dives in cold water, dive year-round in a temperate climate, or value staying warm and dry between dives on a cold dive boat. The upfront cost is higher, but the extended range and comfort are transformative for cold-water divers.