Research suggests that improving mental health nurses’ (MHN) knowledge regarding mental health service provision and cultural responsiveness enhances the Culturally and Linguistically Diverse (CALD) community’s access to mental health services. This three-phased mixed-method research project was part of a larger study that involved developing and implementing an education package for MHNs to investigate their cultural awareness and responsiveness to the CALD community. In Phase 1, a baseline survey (n=80) using a cultural competence assessment instrument (CCA) was conducted to assess the cultural competence behaviours (CCB) and cultural awareness and sensitivity (CAS) of the MHNs in a Victorian metropolitan health service. During Phase 2, an education package was rolled out for MHNs, and a post-intervention survey was conducted, followed by another survey after three months. The survey findings were analysed using IBM SPSS 28 version. The CCA’s reliability score (Cronbach’s alpha =0.89) was high, and Factor Analysis (FA) supported the instrument’s construct validity. The demographic characteristics and prior training/competencies on participants’ cultural awareness were consistent across three phases, except for age, race/ethnicity and participants’ length of experience in MH services. The analysis of Phase 1,2, and 3 survey responses revealed no significant differences in cultural competencies, awareness, and sensitivity among the participants, although the comparison of mean scores of CCB slightly higher improved following the intervention but not the CAS scores. The study concluded that one-off training is inadequate to improve cultural competency (CC), awareness and sensitivity; instead, rigorous mandatory face-to-face training and CC skills assessments as part of continuous professional development are required would be imperative to improve MHN’s knowledge regarding mental health service provision and cultural responsiveness.