Role-playing simulations can provide students with experiential learning opportunities to develop strong interviewing and diagnosis skills, and practice skills they are learning in their classes. In this study, students completed role-playing activities in an online 3D virtual counselor training facility, and interviewed "patient" avatars with mental illnesses to compare their learning with other typical learning activities. Through implementing instructional methods, an environment, "patient" avatars, and other resources created based on the instructional needs, the instructor, assistants, and students were provided an opportunity to use an online 3D virtual environment for experiential learning experiences. The results determined students perceived using an online 3D virtual environment as beneficial. Students reported they perceived that they learned more during their activities in the online 3D virtual environment than other learning activities and using an online 3D virtual environment for role-playing is an effective method to develop mental health interviewing and diagnosis skills.