You should use a well-fitting specific wetsuit, such as those designed for triathlons.
These are usually made from a flexible neoprene that allows you to swim normally whilst helping to insulate the body against the cold water.
Wetsuits should be a minimum of 3mm thick (5mm for those who suffer more from the cold)
The most important thing is that whatever wetsuit you decide to wear – surfing, shortie, short arms and legs – it fits well.
It should be snug when you put in on, so the water is trapped next to your body to warm you up. It should not be loose fitting, so the water flows through it, as this will not warm you up and could restrict your swimming.
We recommend that you try the wetsuit out before event day, even if this is in the swimming pool.