Types:

Wetsuits come in different thicknesses depending on the conditions for which it is intended. The thicker the suit, the warmer it will keep the wearer. Because wetsuits offer significant protection from jellyfish, coral and other hazards, many divers opt to wear a thin suit which provides minimal insulation (often called a "bodysuit") even when the water is warm enough to comfortably forego insulating garments. A thick suit is stiff, so mobility is restricted; at a certain thickness the suit would become impractical, which is why drysuits must be worn in particularly cold environments. A wetsuit is normally described in terms of its thickness. For instance, a wetsuit with a torso thickness of 5 mm and a limb thickness of 3 mm will be described as a "5/3". With new technologies the neoprene is getting more flexible. Modern 4/3 wetsuits, for instance, may feel as flexible as a 3/2 of only a few years ago. Some suits have extra layers added for key areas such as the lower back.

Different shapes of wetsuit are available, in order of coverage:

• A sleeveless vest, covering only the torso, provides minimal coverage. Some include an attached hood. These are not intended to be worn alone, but rather as an extra layer over or under a longer wetsuit.
• A jacket covers the torso and arms, with little to no coverage for the legs. Some jackets have short leg sleeves like a shorty, others feature leg holes similar to a women's swimsuit. A third style, the beavertail, which was quite popular until the 1980s, had a flap which closed over the crotch and attached at the front with a fastener.
• A shorty or spring suit covers the torso and has short sleeves for the arms and legs. There are also forms of spring suits with long arms and short legs.
• A long john or farmer john/jane (depending on the gender the suit is designed for) covers the torso and legs only; it resembles a bib-and-brace overall, hence the nickname.
• A full suit or steamer covers the torso and the full length of the arms and legs.

Some suits are arranged in two parts; the jacket and long johns can be worn separately in mild conditions or worn together to provide two layers of insulation around the torso in cold conditions. Typically, cold water wetsuits have 12 to 15 mm of material around the torso and 6 to 8 mm for the extremities.

Usually they have no feet or hood, and the diver must wear separate booties and hood made from wetsuit material.

Using hoods: in the thermal balance of the human body, the heat loss over the head is at least 20% of the whole balance. Thus, for the sake of thermal protection of the diver, wearing a well-fitting hood is good practice, even at fairly moderate water temperatures.

A specialized kind of wetsuit, with a very smooth (and somewhat delicate) outer surface is used for long distance swimming and triathlon. These are designed to maximize the mobility of the limbs while providing both warmth and buoyancy.

Heated wetsuits also being tested and will soon be available on the market. These suits have special heating panels integrated in the back of the wetsuit. The power for heating comes from batteries also integrated into the wetsuit.