How to Teach a Toddler to Swim. Drowning and near-drowning cases are the leading cause of death in children, so teaching your child to swim is one of the most important things you can do as a parent. Learning how to swim should be as fun as it is necessary; but while some children are natural water babies, others will fight you every step of the way. The key to teaching your child to swim is eliminating his fear, which is helped by introducing water at a young age. By using the reflexes your child was born with, following important safety rules and guiding him through a step-by-step program, you can teach your child to swim at a very young age.