If you're looking for just a little extra warmth in the water then a thermal is the way to go. They're ideal in that it's breathable and... Read More
If you're looking for just a little extra warmth in the water then a thermal is the way to go. They're ideal in that it's breathable and your movement isn't restricted as much as it would be when wearing neoprene, which can provide some resistance even when it's quite flexible. Breathability means they're wearable in warmer waters without becoming uncomfortable, as well as out of the water. Thermals also act in the same way as a rashie, providing protection from rash, sunburn and stingers with the added benefit of thermal retention.
Thermals can also be used underneath your wetsuit. Maybe you're looking to add some extra insulation without buying a whole other wetty, or maybe you'd just like to create a slightly tighter fit. And of course thermals are applicable in a range of sports, so something you use for freediving is going to work just as well for other diving and swimming applications.
Your poly-fleece thermals feel a little like tracksuit material but they're stretchy and hydrophobic on their outer layer (which just means they repel water from the exterior keeping the interior dryer). The way the material works is that the air helps to wick moisture away from the skin (the interior) to the exterior of the material where it dries.