This study evaluated the impact of a voluntary international online course in industrial design, which applied a Project-Based Learning approach, on the acquisition of competencies among second-year students in the Robotic Engineering program at the University of Alicante (UA). The course, which included participants from two other European universities, aimed to enhance both generic and specific competencies. This study measured the acquisition of nine generic and four specific competencies through two types of analysis: qualitative and quantitative. The qualitative analysis involved a survey assessing students’ self-perceived competency gains, while the quantitative analysis consisted of a written objective test that evaluated the acquisition of specific competencies. The results were compared between 43 students who did not participate in the course and 22 who did. The survey responses indicated that, for 10 out of 13 competencies, students reported an improvement in skills as a result of the course. Additionally, the average test score for participants was 77.2%, significantly higher than the 37.7% score for non-participants. These findings suggest a strong correlation between course participation and competency development, highlighting the potential benefits of international online courses in enhancing student learning outcomes in robotic engineering.