Plogging, a practice that combines outdoor exercise with waste collection, is a novel alternative to physical activity; therefore, it has not been extensively studied in the scientific literature yet. The aim of this research is to analyse whether students’ environmental attitudes are affected by a 6-week intervention based on plogging. A total of 143 students (mean age 15.58 ± 3.28) participated in the study. A pre-post design with control and experimental group was carried out. To assess attitudes, a diagnostic questionnaire of attitudes towards the environment in secondary school students was used. The instrument is composed of five factors (motivation, participation, communication, environment and education). To measure the effect of the intervention, the Wilcoxon signed-rank test was performed. The results showed that the experimental group significantly improved in factors such as motivation and environmental awareness. These results contribute to increasing research on the integration of sustainability in Physical Education.