This paper reports on a study conducted to examine the development of cadets’ soft skills by implementing project-based learning in Moodle LMS during the COVID-19 pandemic. This study was classroom action research following the Kemmis & McTaggart’s model. It was conducted in three cycles, each consisting of plan, action, observation, and reflection. The participants of this study were the cadets from four different study programs at Sekolah Tinggi Maritim Yogyakarta currently enrolled in online classes. The data were collected through observations and focused-group discussions. The results showed that the implementation of projectbased learning in Moodle LMS contributed effectively to the development of the cadets’ soft skills including responsibility, discipline, creativity, and problem-solving. After implementing the projectbased learning for about 16 week-meetings, the researchers recorded the gradual improvement in the soft skills performed by the cadets as follows: 39.42%(low) in Pre-cycle, 52.71% (average) in Cycle I, 69.91% (high) in Cycle II, and 83.71% (very high) in Cycle III. The aforementioned skills were perceived as key fundamental skills required by the cadets to perform their jobs successfully in the 21st century workplace, particularly in the maritime industry.