In recent years, international students' settlement experiences have emerged as a new focus in migration studies. This qualitative study examines the study-to-work transition experiences of 30 mainland Chinese graduates living in Hong Kong and deepens the current discussion of these students-turned-migrants' socio-cultural integration. Specifically, mainland Chinese students-turned-migrants experience ongoing challenges in their study-to-work transitions. Adaptation difficulties in their university years, including limited Cantonese proficiency, meagre cultural understanding of the host society, and weak connections with locals, continue to affect their subsequent employment and social integration. Our findings underscore the crucial links between international students' prior socio-cultural adaptation and their post-study settlement experiences. We also reveal everyday workplace microaggressions, which should receive greater attention from scholars interested in international students' and students-turned-migrants' intra-ethnic interactions. Our findings have implications for immigration policy, university student services, and local companies.