Cultural competence development in social work education requires urgent attention, particularly within Chinese educational contexts where research remains limited. This study examines the effectiveness of bilingual instruction approaches in enhancing social work students’ cross-cultural awareness and perceived professional competence in multilingual contexts. A curriculum-based program delivered through bilingual instruction was built into two specialized courses designed to strengthen multicultural sensitivity and competence development. Between February and April 2025, sixty-two social work students participated in the program. Questionnaires were used to assess the effectiveness of bilingual education in developing participants’ cultural sensitivity and professional skills. Multiple regression results demonstrated that cultural awareness serves as a critical mediating factor in the relationship between awareness of others and perceived social work competence within multilingual contexts, with this positive influence particularly evident through the cultural awareness dimension of social work cultural competence. Additionally, findings supported the positive effect of cultural awareness and the significant contribution of skill development to perceived competence, while the mediating roles of knowledge acquisition and practice competence were not statistically significant. These findings have implications for designing culturally-inclusive social work programs and strengthening preparation for international practice contexts.