Wetsuits and Drysuits

What sort of exposure protection should you wear?  It depends on a few things, including:
  • Where you're diving
  • How long your dives are (longer = more protection needed)
  • How deep you're going (wetsuits compress with depth, so deeper = more protection needed)
  • How many dives a day you're doing (when you're tired, you get cold faster)
  • Are you swimming around a lot (burning more calories) or not moving much?
  • Your personal temperature tolerance.
Here are some useful guidelines.



Water temperature at depth: 48 - 58 (year-round).

5mm gloves and hood are essential.

Good choices:
  • Drysuit
  • 8/7mm semi-dry wetsuit
  • 7mm full wetsuit with 6/4mm hooded vest
  • 7mm two-piece wetsuit
All wetsuits are no fun below 60' for more than 20 minutes, because the depth compresses the insulation.  If you're diving deeper, there is no alternative to a drysuit other than a freakishly high metabolism.

Southern California

Water temperature at depth: 58 - 71

Good choices:
  • Drysuit (winter/spring)
  • 8/7mm semi-dry wetsuit
  • 7mm full wetsuit with 6/4mm hooded vest
  • 7mm two-piece wetsuit
  • 7mm full wetsuit (summer/fall)
The water is at its warmest in the summer and fall.  In the winter and spring, it's not much warmer than Monterey.  The wrecks off of San Diego are deeper, and more exposure protection is needed.

Hawaii or Fiji

Water temperature at depth: 75 - 82.

On the colder end in the winter and spring, particularly in Kauai.

Good choices:
  • 5mm full wetsuit (add a beanie if you get cold)
  • 5/3mm full wetsuit
  • 3mm wetsuit (if you're only doing 2 dives/day)


Water temperature at depth: 77 - 82.

Good choices:
  • 5mm full wetsuit
  • 3mm full wetsuit (add a 3mm hooded vest if you get cold)


Water temperature at depth: 82 - 84.

Good choices:
  • 3mm full wetsuit
  • 3mm shortie

Types of Exposure Protection


A drysuit is more or less a waterproof bag that you wear fuzzy pajamas underneath.

I mostly dive drysuit now (custom-fit DUI), but that's a bit more of a financial commitment.  It stays the same insulation from the surface down to >100' (and is actually a bit warmer at depth than near the surface.  The extra warmth comes in handy when doing macro photography, because I'm holding very still for long periods and wearing 2mm gloves so it's easier to operate the camera.  And when teaching, because though the *students* are flailing around burning calories and air, I'm mostly holding still so not generating much heat.<

Drysuits are more buoyant than wetsuits because they're full of air.  Expect to wear more lead.  It's a good idea to wear a good chunk of it in a weight belt to ensure you don't overload the buoyancy of your BCD, and keep your feet from being floaty.

Diver Dan's rents drysuits.

8/7mm Semi-Dry Wetsuit

For example, the Aqualung SolAfx.  This is a single-piece wetsuit with extra baffles and a waterproof zipper to reduce water flow, and an integrated hood.  It's as warm as a 2-piece wetsuit, but with less buoyancy.

I own the SolAfx and have done dives down to 48 degress and as long as 84 minutes.

Breakwater Scuba rents semi-dry wetsuits.

Full Wetsuit

These come in a variety of thicknesses, from 3mm up to 7mm.  They're basically a neoprene onesie.

If you're diving somewhere a bit chillier or your head gets cold, you can add a beanie or a bibbed hood (the bib tucks down into the neck of the wetsuit).

With Hooded Vest

Sometimes a full wetsuit on its own is not warm enough.  You can add a hooded vest to get more insulation over the core, and with the integrated hood it keeps your head warm with less water leakage than a standalone hood.  Hooded vests can be as thin as 3/2mm (3mm hood, 2mm core) or as thick as 7/5mm.

If you're going someplace warmer, you can reuse the full without the vest, or the vest over a thinner full wetsuit.

Two-Piece Wetsuit

The bottom piece is overalls.  The top piece is a long-sleeve "Farmer John" or "Farmer Jane" with short legs.  You'll also need a hood; tuck that under the farmer john.

Most shops in Monterey rent these because it's somewhat easier to fit different body shapes.  These don't tend to fit as well if you're really skinny; in that case, you're usually better off in a Semi-Dry (see above).

There are a few downsides to this setup:
  • More places for water to leak in if it's not snug all over
  • Thick neoprene, so you'll need to carry a few pounds more lead than a semi-dry or full+hood.

Shortie Wetsuit

This has short legs, and may have long or short sleeves.  Due to the amount of exposed skin, it's usually for warmer water only, or on top of overalls as part of a two-piece wetsuit.