This present thesis investigates the didactic concept of a swimming lesson for children with trisomy 21 (down-syndorme). At first, it focuses on the down syndrome, its history and clinical presentation, as well as divergent motor skills, which are connected to it. Since these swimming lessons take place within the scope of Special Olympics, this thesis also aims to describe this particular sport movement and their organized events. Water and the movements taking place in it have various effects on children with trisomy 21, which can be categorized in biochemical, physiological and psychological factors as shown in this thesis.In swimming, there is a variety of training principles, of which five will be presented exemplary. These will be examined in the subsequent chapter, which deals with the didactic concept and is additionally based on experience values.The aim of this thesis is to illustrate characteristics of good teaching practice, which emerged during the work in cooperation with Special Olympics.