INTRODUCTION: Telehealth is crucial to the provision of high-quality treatment of critically unwell patients in rural areas. Our aim was to explore the benefits and limitations of a mixed reality (MR) headset for clinician-to-clinician telehealth in a simulated rural context, in which the advising clinician directly views the treating clinician's point-of-view and uses holographic annotations to provide visual guidance in three-dimensional space. METHODS: Twenty-five clinicians trialled a MR headset-the Microsoft HoloLens 2-and evaluated it against a trolley-based videoconferencing device used in current practice. Each participant trialled the devices while role-playing one of two perspectives: the Rural Clinician accessing support or the Advising Clinician providing support. RESULTS: Advising Clinicians had higher ratings of usability and self-efficacy, and lower ratings of mental workload, when providing support via the MR headset compared to the videoconferencing trolley (ps < 0.035). However, Rural Clinicians rated the MR headset lower on usability compared to the videoconferencing trolley (p = 0.020), and rated their self-efficacy and mental workload equally when using both devices (ps > 0.253). Participants generally preferred to use the MR headset over the videoconferencing trolley. On average, scenarios took 1 minute longer to complete when using the MR headset (p < 0.001). DISCUSSION: Wearable MR technology has the potential to improve the quality of support provided to rural clinicians; however, it may be more beneficial for those dialling in to the device (advising clinicians) rather than those wearing the device (rural clinicians). Factors that may limit its safety and efficiency are discussed.