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Part 1 – Buying an exposure suit for scuba diving

A dive exposure suit is used during SCUBA diving to protect the diver underwater. You need protection from exposure to the temperature and the environment. There is cold, heat, and critters with all manner of defense mechanisms down there. You want to be safe from hypothermia and physical harm. So, how do you choose the right wetsuit for you?

A wet suit is made from various materials including Neoprene. They are designed to preserve core warmth and prevent hypothermia. Neoprene is spongy fabric with air filled cells that are capable of repeatedly expanding and contracting in response to pressures at various underwater depths.  The wet suit slows the entry of cold water into the suit near the diver’s skin. In doing so, body heat is preserved during the dive. Wet suits come in several thicknesses (measured in millimeters of width of the fabric). The 0.5mm, 2mm, 2/3mm, are for warmer environments. While the 5/7mm, and 7mm are for cold water diving.  There are also different styles of wet suit, providing protection to various parts of the body. Additionally, gloves and hoods serve as exposure protection for the hands and feet.

As you go deeper when you dive, pressure compresses the air filled cells in the neoprene suit. As the neoprene compresses it provided less protection from heat loss. So, when you dive in colder water, or deeper depths, you need a thicker wetsuit. In warmer waters a 0.5mm exposure suit (also known as a “skin”, or wetsuit) may be sufficient, with the goal of protecting you from coral scrapes, sunlight, and invisible stinging “floaties” in the water. After repeated dives, the neoprene tends to lose the ability to decompress after diving, resulting in reduced heat loss protection for the diver on pending dives. The age of the suit and number of dives it has had become important factors when considering the purchase of a used suit. I will discuss this further in part 2. Thankfully, wet suits are a relatively inexpensive form of underwater exposure protection. So if you dive frequently, replacing your dive suit frequently doesn’t have to be a financial disaster.

A semi-dry wet suit is a form of wet suit that provides extra protection from heat loss while diving in colder water. The semi-dry suit is made of neoprene fabrics, like a regular wet suit. The addition of neck, wrist, and ankle seals, reduce water exchange and improve heat retention during the dive. Cold water is kept away, allowing the diver to stay warmer longer at depth. The semi-dry suit is slightly more expensive than a wet suit.

A dry suit is used for diving in very cold water. The suit (“shell”) is made of waterproof fabrics, with neck and wrist seals, and boots. This type of suit prevents water from entering the suit at all. Air is added inside the suit during the dive to insulate the diver from the outside cold temperature and prevent “squeeze”. The diver wears warm clothing underneath the dry suit “shell” for added warmth during the dive as well. Dry suits are much more expensive than a wet suit or semi-dry suit, but are a good investment if you plan to dive cold water frequently.

Temperature ranges for the various types of suits can be found in the table below:

Wetsuit Temperature Guide

Water  Temp.
Range (°F)
Suit mm Suit Type Seal
>72° None – 0.5mm Bathing suit/rashgaurd None
65°- 75° 1mm – 2mm Neoprene shorty, shirt/shorts None
62°- 68° 1/2mm – 3mm Long sleeve/leg, Farmer John None
58°- 63° 2/3mm – 4mm wet suit  glove/hood/boot Wet /Semi -dry
52°- 58° 3/4mm –  5mm Wet suit hood/glove/boot Wet  /Semi-dry 
43°- 52° 5/7 mm – 7mm Wet suit hood/glove/boot Wet /Semi-dry/Dry 
42° and below 7mm or more Wet suit  /boot/glove/hood Dry  


Look for Part 2 – Buying an exposure suit for SCUBA diving, where I discuss shopping, fitting, and pricing exposure suits. You can look through my previous blogs for some additional information on buying used gear, there is often crossover information between blog subjects. And as always, feel free to email blueorbsales@gmail.com with questions.

Authored by Lisa J Henry

“Be the sea”