Boxing involves a high risk of dental trauma due to the impact of enormous external forces against the head. Wearing a mouthguard is, therefore, mandatory. The aim of this study was to evaluate the prevalence of dental trauma as well as the utilization and quality of mouthguards in Swiss boxing clubs. In order to achieve this, data on the mouthguards of 217 boxers in total were collected using questionnaires and examination forms, which were statistically evaluated. Out of the 217 boxers, 75 (34.6%) had already experienced a dental accident, but only 8 (10.7%) of them while practicing their sport. Professional boxers were most frequently affected by dental trauma (p = 0.001). Crown fractures were most often observed, followed by tooth dislocations. All interviewed athletes owned a mouthguard, which they used much more consistently during full-contact sparring (practice fighting) than during regular partner exercises. Most of the boxers used prefabricated mouthguards, which could be individually adapted using the boil and bite system. The majority of the athletes received their mouthguards from the boxing club. Impaired speaking when wearing a mouthguard was, by far, the problem most frequently mentioned by the athletes. In terms of these bothering factors, custom-made mouthguards from dentists received the best rating (p = 0.002). The quality of the mouthguard was assessed by evaluating the following criteria: coverage of the buccolabial surface, occlusal support of the opposing dentition, thickness of the occlusal layer, and rounded edges. Of the 215 mouthguards examined, 193 (89.8%) were insufficient (p = 0.002). Despite the observed deficiencies, only a few dental injuries occurred during boxing. This study shows that although basic preventive measures do exist in Swiss boxing, they should be improved substantially by providing better instruction and more information.