A study of the Danish Swimming Federation shows that there is a decrease in members aged 8-12 years (Nielsen, 2014). Several studies have examined participation in sports, including two Danish studies of soccer (Hansen, 1998; Østergaard, 2009) and several foreign studies of swimming (Jakobsson, 2014; Light, 2010; Light 2011; Paquette and Smith, 2009; Woods et al., 2007). The above foreign studies brings a focus on participation, where children and parents are involved in relation to motivation. Danish studies have focused on children and parents primarily through questionnaires and individual interviews. The influence of the environment on participation have been the focus in several foreign studies (Light, 2010; Ligth, 2011; Paquette & Smith, 2009). Inspired by the lack of Danish studies examining the importants of the environment and motivation I have found it interesting to examine this in Gladsaxe Svøm. This environment was chosen to be examined due to a change in structures for the purpose of maintaining swimmers. The purpose of the casestudy is to examine how the environment stimulates swimmers motivation. The study took place over a period of two months from the 28th of February to the 26th of April, where two weekly training sessions and three social events were observed. In addition to these observations questionaires and qualitative interviews with coach and sportsmanager (n=2) and swimmers (n=8) were undertaken. The interviews and parts of the observations were designed on the basis of the Self-determination theory's three basic needs and provides the basis for the analysis. The study indicates that the environment with structural changes stimulates the swimmers motivation in varying degrees, depending on the specific day. The study therefore gives an insight into how an environment and the actions in it, affects swimmers motivation. This knowledge is relevant for clubs who wish to develop plans aimed at maintaining children in swimming. Keywords: Swimming, motivation, children.