The purpose of this study is to figure out the views of pre-service teachers on the usability of three-dimensional simulation-based teacher training simulations. For this purpose, the opinions of pre-service teachers regarding the use of three-dimensional teacher training simulation called "SimInClass" were taken. The participants were 39 university students in their junior years who had taken "Classroom Management", "Instructional Design" and multi-user virtual-environment design courses from a state university, from the Faculty of Education, Department of Computer Education and Instructional Technology (CEIT), in Ankara, Turkey. The pre-service teachers used simulations in a computer lab. In the orientation of the students, they used "Start Tutorial" part of the simulation for 10 minutes, and then they experienced the teacher training simulation as "teachers" for 60 minutes. After the implementation, data were collected via an online questionnaire, which was developed by the researchers. In addition, evaluation records which measure the level of knowledge and concentration of the class of the simulation were used, as well. According to this, it was observed that the teacher training simulation is easy to use and offers an opportunity to experience a real classroom environment. Moreover, candidate teachers expressed an increase in their awareness about situations such as preparation of lesson plan, classroom management, time management, and classroom control according to the number of students and strategy development for undesirable behaviors. It is therefore stated that "SimInClass" can be used as an auxiliary tool in the professional development process. However, it is noted that the interaction between the teacher and the student in simulations is limited; the feedbacks are insufficient and flow quickly from the screen, making it difficult to read the feedbacks. In addition, students also reported that the sound effects are insufficient and the simulation slows down the computer when it is used at a high resolution.