1. Wear two caps. You lose most of your heat through your head
2. Wear a neoprene cap. Neoprene is better suited for cold water than standard latex.
3. Neoprene socks are a good idea, but you may want to use these mostly on training swims, as they can be a hassle when it comes to transitioning to your bike on race day.
4. Wear a wet suit—but more specifically, a full suit. The sleeveless suits allow heat to escape through your armpits. Keep in mind that, according to USA Triathlon rules, wet suits are allowed at triathlon’s with water temperatures of 75 degrees Fahrenheit or below.
5. Put in earplugs. When the water drops below 60 degrees they do work well in keeping your core temperature up.
6. Practice swimming in cold water. At first, it can be a shock to your system that can lead to hyperventilating or a panicked feeling. You will want to swim slowly until you catch your breath. The first time you experience this it can throw you off, but with practice you will get used to it and be able to relax into your swim.
7. Do a significant warm-ups (10 to 15 minutes, minimum). This will decrease the shock effect that cold water can have and allow you to get into a stroke rhythm much faster.
8. Blow bubbles before taking off on your swim. When the cold water hits your face, the shock causes your lungs to contract, causing breathing problems. Go waist deep into the water and submerge your face to blow bubbles. This helps alleviate the shock of the cold water.