A man scuba diving with a school of fish. We want to know what thickness wetsuit do I need for these temperatures.
Scuba diving with a school of big eye trevally. Photo by Hiroko Yoshii / Unsplash

As a scuba diver, it is imperative to pay special attention to the water temperature as you prepare for a dive so that you stay comfortable and, most importantly, safe. When deciding what thickness wetsuit do I need, you will need to consider the water temperature you will be immersed in.

The human body loses heat much more rapidly in water than in air, a rate that increases as the water temperature decreases. Fortunately, clever developments in materials technology mean that humans can dive in all of the world’s oceans with the right level of exposure suit. (For near-freezing temperatures you’ll need the right mental attitude, too!).

What Thickness Wetsuit do I Need

Infographic on wetsuit temperature guide scuba, snorkel, surf & more

When to wear a thin skin suit or rash guard

In truly tropical waters, such as diving in Thailand or the Caribbean, many divers will choose to dive in a “skin suit” or a rash guard – a very thin layer which prevents the BCD rubbing on the skin, and blocks out the sun’s harmful rays.

Find out how rash guards can keep you warmer.

Many divers do not think about sunburn or sunstroke whilst diving, but the sun’s radiation can still affect you underwater and so it is always advised to use at least a thin skin suit that covers most of your body. Sunburn leads to dehydration which leads to bad news for scuba divers!

When to wear a wetsuit

In warmer climates, the most common form of exposure suit is the wetsuit. They vary in thickness from 2mm to 7mm, and are excellent at keeping you at a comfortable temperature on a dive.

Local dive shops should always be able to give you the best recommendations for your chosen dive site and time of year.

It is worth noting that thicker wetsuits can start to restrict mobility if you are not used to them, and divers should be aware of this and comfortable in their gear before starting a dive.

When to wear a drysuit

If diving in a cold country such as Norway, where it can get below a certain water temperature – around 16℃ for most people – some dives require a different type of suit. In contrast to the wetsuit, the drysuit should keep everything but your head and hands completely dry.

With in-built boots and tight latex or neoprene seals at the wrists and neck, drysuits trap a layer of air – an excellent insulator – between the suit and your skin. As with thicker wetsuits, drysuits can further restrict your mobility and, in some cases, feel claustrophobic.

In addition to the lungs and BCD, the layer of air in the drysuit can also be manipulated to aid a diver’s buoyancy. They contain a chest valve with hose attachment for pumping air in, and generally a shoulder or wrist valve for dumping air out.

Most organizations treat drysuit diving as a completely separate skill, and offer a specialized certification. If you are new to drysuit diving, it is always recommended to gain complete confidence in a drysuit first before attempting more challenging dives.

Read more about how a drysuit works and things to consider when using a drysuit.

When to wear a semi-dry suit

For divers at “inbetween” temperatures who want something more substantial than a wetsuit, but do not fancy the unfamiliar sensation of a drysuit, then a “semi-dry” suit may be the most appropriate. A sort of halfway house between the two, a semi-dry does let water in, but has tighter seals at the neck, wrists and ankles. This stops water from “flushing” through the suit, and the layer of water trapped against the skin is warmed up by the body over time.

If you know the water temperature of your next dive, then head over to our wetsuit temperature guide to find out ‘what thickness wetsuit do I need’ to ensure your comfort and keep you feeling nice and warm!