During the swimming segment, you can either choose to wear a wetsuit, a tri suit or a pair of tri shorts. A wetsuit is great for swimming in cold temperatures because it has thick rubber outer and base layers that provide both buoyancy and warmth. Some races prohibit the use of wetsuits depending on the temperatures, so be sure to check the rules and guidelines of your specific triathlon event. They are also available for rent in many stores.
A tri suit is a one-piece that allows you to complete the entire race without changing. This is a great option to save time during transitions, but keep in mind that the tri suit is just a base layer that does not provide warmth and protection against low temperature waters. A tri short is similar to a tri suit and is a good choice for those who are uncomfortable wearing a one-piece.
You will also need swimming goggles and a swimming cap. Choose goggles that are comfortable and durable and have good visibility.
Ear plugs are optional for wear. They are great for keeping water out; get a pair that is durable and dependable.
When transitioning from swimming to cycling, you may want to consider bringing a towel for changing and drying yourself. If you are wearing a tri suit, you can just dry off, put on your socks and shoes and get on your bike. If you're wearing tri shorts, you can opt for a top that is comfortable for biking.
It is best to wear shoes that are designed for both cycling and running so you do not have to change during transitions. However, many athletes are particular about their bike shoes and running shoes.
You will also need a helmet, sunglasses and biking gloves. Choose biking gloves that fit well and provide ample grip control and protection for your hands.
If you are wearing a tri suit or a pair of tri shorts, you will only need to change into your running shoes. You may want to bring elastic or quick laces to save some transition time. There are specific triathlon running shoes available; if you buy new ones, make sure to break into them properly.
Wear a cap or visor to shield against the sun and sunscreen to protect your skin. It is always good to prepare for unforeseen weather changes, so aside from a cap, visor and sunscreen, bring extra clothing just in case it rains.
Do not wear anything new for the race day. It is best to wear athletic gear and accessories that you are accustomed to in training. It is best to be comfortable and familiar with your clothing so you can focus on your speed and performance.