Developing oral presentation skills is an essential objective of higher education. While previous research emphasized the importance of practice for developing oral presentation skills (OPS), it remains unclear what the optimal amount of practice is. This experimental field study examined the added benefit of an extra practice session in virtual reality (VR) on the progression of 35 graduate students in OPS, using a pre-test post-test design. In addition, the mediating effect of public speaking anxiety (PSA) was examined and the relation between PSA, preparation practices, perceived utility of VR and OPS was explored. Questionnaires and performance assessments were used in data collection. Results showed that participants gained benefits from practicing a third time before a virtual audience. Both anxious and non-anxious participants progressed similarly on presentation skills and experienced the VR intervention comparably. However, the optimal number of practice presentations remains unclear and should be further investigated.