Researchers examining carbon dioxide-equivalent emissions (carbon footprint) in sport have focused on sport events and, to a lesser extent, sport teams, but provided only average or aggregate values. The author takes the perspective of active sport participants and considers the heterogeneity of individual sport participation behavior. Using online surveys, adult active sport participants (n = 6537) in 20 different sports with main residence in Germany were asked to report their sport-travel behavior in 2015, including traveling in the context of regular (weekly) activity, sport competitions/tournaments, league games, day trips, and training camps/vacations. Annual carbon footprints were estimated using information about travel distances and transportation means. The results revealed an average annual carbon footprint of 844 kg of carbon dioxide-equivalent emissions, with individual sports producing more emissions than team/racket sports. Participants in nature sports had the highest emission levels. Regression analyses revealed that environmental consciousness significantly reduced carbon footprint in individual sports, but not in team/racket and nature sports, supporting the existence of an environmental value-action gap. Activity years, club membership, weekly exercise hours, performance level, and income were mainly positively associated with annual carbon footprint, while gender was insignificant. The findings have implications for policy makers and managers in sport associations and clubs.