Triathlon has grown in the recent years tremendously. Therefore, it is important to gain more understanding for the environmental impact triathlon causes. The purpose of this study is to investigate the carbon footprint that is caused by transportation and travel behavior of triathletes. Moreover, the determining factors of the carbon footprint are examined. Data on distances to training, competition and training camps in the year 2015 was collected by an online survey in Germany (n=413). Using this information, the carbon footprint could be calculated to ascertain the amount of emissions of triathletes. Results show that triathletes comparatively have a high carbon footprint (Mean: 774kg CO2-e).This topic revealed the need for action in strengthening the environmental awareness of every involved actor. Furthermore, there should be more either individually or organizationally driven initiatives to minimize environmental impacts such as carbon offsetting or carpooling.