Across East and Southeast Asia, the International Baccalaureate (IB) is expanding and diversifying. More students from affluent families are 'opting out' of mainstream schooling to take the IB's Diploma Programme (DP), which is marketed as a distinctive skill-based education that prepares students for university. This research investigated how DP alumni reflect on their educational experiences in developing cognitive and non-cognitive skills and as preparation for elite universities in Hong Kong. An online undergraduate survey (n = 734) found that DP alumni self-perceived higher capacities than non-DP alumni in communication, creativity, critical thinking, cultural sensitivity, global-mindedness, leadership, and time management. In interviews (n = 42), DP alumni perceived the DP as a privileged educational experience that 'worked' in developing cognitive and non-cognitive skills. The DP alumni were overall positive about their DP experiences in developing skills for university preparation. However, there were complexities as the DP alumni also perceived that students from mainstream schools were often better prepared for pedagogy and assessments in the context of higher education in Hong Kong.