Introduction. Endurance running may lead to heart remodelling. There are little data on the right ventricular (RV) changes in amateur athletes running shorter than marathon distances. The study aimed to investigate whether training and running a half marathon affect the anatomy and function of the RV in amateur runners and whether these changes affect the athlete’s competitive performance. Material and methods. The study included 45 recreational runners with a mean age of 32.96 (5.12) years, 27 men. Echocardiography was performed before the ten-weeks training period and before and after the half marathon run. The morphological and functional parameters of the RV were analysed, including two-dimensional, Doppler and speckle-tracking echocardiography. Results. In training period, the RV outflow tract (27.98 [5.46] vs. 30.07 [4.90]; p = 0.003) and the RV index of myocardial performance (0.36 [0.29; 0.45] vs. 0.39 [0.33; 0.52]; p = 0.017) increased significantly and no changes were found for E/e’. After the half marathon run, the absolute value of the RV free wall global longitudinal strain increased significantly (–25.89 [3.08] vs. –27.20 [3.42]; p = 0.008). Athletes who trained more intensively during the training period achieved significantly better half marathon results (r = –0.4; p ≤ 0.05). Conclusions. More enhanced physiological RV remodelling under exercise in amateur athletes results in better half marathon finishing times. The preparation period and 21.0975 kilometres run do not affect the diastolic function of the RV in recreational runners. The RV systolic function improves immediately after the half marathon performance.