If you have not spent much time in water with your young child, then it is best to wait until your child is three or four years old, before sending them to independent swimming lessons.
For children under two, there are parent-toddler water orientation classes, where you are in the pool with your child. This allows your child to gradually overcome any fear of water and build skill and confidence for future lessons.
Formal swimming lessons are too difficult for a toddler to understand or get any real benefit from. Toddlers cannot comprehend complex instructions and will be unable to follow safety commands, so the experience could be dangerous too. Swimming classes are generally divided into groups, which consist of children of similar ages and skill levels. These small groups allow for close observation and effective teaching from the swimming instructor. Beginners are taught how to hold their breath, float, kick, and use their arms. As their experience increases, more complex swimming techniques are taught.