Undersuits for Drysuits

A drysuit without sufficient undergarments is like a cold apple crumble and no custard! Your drysuit should keep water out but it is your undersuit that does the lion’s share of the work with the insulating properties that keep you toasty warm.

Gone are the days of the “woolly bear” that was inflexible and bulky. Today most undergarments are made from innovative low buoyancy materials that are machine washable and stretchy. Here at Mike’s Dive Store, we have a massive range of undersuits ranging from thin base layers to thick heavier duty suits. Some are specially designed to be worn with certain types of drysuit while others can be layered for different diving applications. 

1. Base Layers: This close-fitting part of your underclothing will keep you dry by wicking water -like perspiration- away from your skin. A dry area is better insulation than a wet one that will cool your body. Some base layer products are odour resistant and have anti-fungal properties like the Fourth Element J2 Baselayer Set. Some can be worn in warmer climates but generally, a base layer is designed to go underneath an undersuit in colder water.

2. Undersuit (the thermal bit): Usually made from a fleecy material, your undersuit should trap your body heat, creating insulating layers of air between each layer of clothing. Choosing the right one will depend on 3 things – the type of drysuit you are wearing, the water temperature and the duration of your dive.  Undersuits come in either one-piece or two pieces and some have padding in crucial core areas where you will lose heat fastest as seen on the Waterproof 3D Mesh Vest. Fourth Element undersuits are used by the Swedish, Danish and French Navy, Dutch Special forces, FBI teams and British Police diving teams, proving their worth in the cold and for arduous activities. Heavier duty classic undersuits such as the Waterproof WarmTec have thick fibre fills like a sleeping bag and are often favoured by UK divers for their longevity.

3. Heated vests and undersuits: For an added boost of warmth on chilly diving days, heated undervests and accessories are designed to protect your core and extremities from the cold. They are favoured by the technical community for long extended range dives. With some available wireless temperature controls and long rechargeable battery life, these items were once considered a luxury but now are being seen more and more in everyday diving environments. We love the Thermalution Yellow Grade Plus Heated Undervest and Full Set Stand-Alone Heated Gloves. The other big brand here is Santi who do a range of heated vests, gloves and undersuits. They will genuinely take your diving to the next level!.

Still not sure what type of undersuit you need or how thick it should be? Read our Choosing a Diving Undersuit guide for some helpful advice about different kinds of undersuits, materials and thicknesses and how they pair up with the various drysuits on the market.