While itsy bitsy bikinis and board shorts are standard on the beach, competition swimming needs a more substantial suit. Competition swimsuits are made for speed, so they offer wider coverage and a tighter fit than casual swimsuits. Each brand of competition swimwear fits differently, so measure yourself and then compare those measurements to the sizing chart for each specific brand. This will allow you to achieve the best fit so you can take your swimming to the next level.
Measure your body. Men should measure both the waist and seat or hips, while women will need to measure their chest, waist and seat. If you've swam in competitions in the past, measure yourself again each year to ensure the best current fit for your body.
Compare your measurements to the sizing charts for various brands. Each brand fits differently, so never assume that you're the same size in more than one brand. Knowing what size you are for each brand can help speed the purchasing process, particularly if you're purchasing your competition suit online. Sizing charts can be found online or in sporting good supply stores.
Order up one size if you fall in between sizes according to a manufacturer's sizing chart. Competition swimwear is meant to fit snugly. The material is meant to compress your body, which means competition suits can feel very small. Ordering up a size will offer a better fit. Suits that are slightly larger are especially appropriate for training, then you can purchase a better fitting suit for competition purposes.
Try on competition swimsuits, if possible. While custom brands may only allow you to try on sample suits before ordering, more readily available brands can be found in sporting good supply stores, where you can try the suit on to ensure the right fit. Competition swimwear should fit tightly but never impede your movement or become uncomfortable. Put the swimsuit on while wearing undergarments and practice moving your body in a variety of directions to ensure the suit is comfortable.