Japan, in 2016, was ranked among the top four host countries of inflows of international tertiary-educated students among OECD countries, and it occupied the top position in the non-Anglophone country category. Alongside the “300,000 International Students Plan” announced in 2008, Japan introduced a direct policy pathway for study-related migration. Although Japan has become a key nation for international student mobility/migration (ISM), ISM research pertaining to Japan is scarce. By exploring the issue from the angle of facilitation of international university students’ education-to-work transition, this case study attempts to identify the key factors that helped or hindered career decision-making and job search of international STEM master’s students of English-taught programs in Japan. Drawing on primary data from the surveys conducted in a particular university, aspects that are considered to have some influence on international students’ decisions pertaining to their career path and their career outcome are explored. The findings are relevant to international students, career supporters, universities as well as policymakers, since Japan needs to form posts for the “300,000 International Students Plan” as this was the target set for 2020.