Physical activity increases body immunity by adjusting the exercise intensity of each individual with mild-moderate exercise at a threshold of 60-80% of the maximum pulse rate. This research aims to inquiry the effect of online physical activity program which was implemented during physical education class toward physical fitness. There was endurance, upper body strength, core strength, and lower body strength as the selected component of physical fitness in this study. Research and development (R&D) and quasi experimental study with a one group pretest-posttest research design were implemented in this study. The physical fitness was measured by skipping, push up, plank and horizontal jump. There were 250 undergraduate students who enroll in physical education and fitness courses participated in this study as research sample. The online physical education program was implemented in 4 months. The result, there was a significant improvement on students’ upper body and core strength (sig. < .05). Furthermore, the results and discussion are explained further in the article.