Background: There is a high prevalence of orofacial trauma in rugby union players. Mouthguards reduce complications following dental injuries, should dental injuries occur. The aim of this study was to investigate the prevalence of oral trauma and the significance of mouthguard use in adult amateur rugby union players in New South Wales, Australia. Methods: Questionnaires were distributed to players in rugby union clubs. It questioned players about their mouthguard use and orofacial trauma experience; the type of injury, complications, if a mouthguard was worn, where treatment was sought and outcome. Results: The prevalence of orofacial trauma in rugby union players is 64.9%. The most common injury was laceration to intraoral and extraoral soft tissues at 44.5%. Of all orofacial injuries reported, 41.9% were to the dentition. Following dental injury, loss of the tooth was the most common complication (34.7%). 76.9% of players wore mouthguards. By wearing a mouthguard, the risk reduction for ongoing complications following dental injuries was 18.5% (p-value = 0.009). Of these, 10.4% (p-value = 0.45) represented loss of the tooth. Conclusions: Rates of orofacial trauma and complications in amateur rugby union players are high in Australia. Use of mouthguards results in significant risk reduction for complications following dental injuries, including loss of tooth.