Ankle sprains are the most common acute injury among dancers and may result in the development of chronic ankle instability (CAI). Chronic ankle instability is characterized by recurrent ankle sprains, incidents of the ankle "giving way," and sensations of instability and has been reported to negatively impact functioning and psychosocial status. The large number of ankle sprains in addition to contextual factors relating to professional dancing, suggests that CAI may be a significant problem in professional ballet dancers. This study aimed to determine the prevalence of CAI and describe the ankle injury history and level of self-reported function in South African ballet dancers. This descriptive, cross-sectional study included all professional ballet dancers employed by three professional South African ballet companies (n = 65). The Identification of Functional Ankle Instability Questionnaire (IdFAI), Foot and Ankle Ability Measure (FAAM), Dance Functional Outcome Survey (DFOS), and a researcher-developed injury history questionnaire were completed by consenting participants. Descriptive statistics were calculated. A CAI prevalence of 73.3% CI [55.6%, 85.8%] was calculated among 30 participants. Twenty-five (83.3%) participants reported sustaining at least one significant ankle sprain with 88% (n = 22) indicating dance related activities as the cause. Dancers with CAI demonstrated a tendency to have less control over their ankles giving way and tended to take longer to recover from their ankles giving way than those dancers not affected. Eight participants (36.4%) with CAI were identified as having a significant level of disability on the FAAM activities of daily living (ADL) subscale and six participants (27.3%) on the sport subscale. Participants with CAI had a median total score of 83.5; IQR [80 - 90] on the DFOS. The self-reported function of South African professional ballet dancers is not severely affected, however, the high prevalence of CAI and reported symptoms is concerning. Education on CAI symptoms, prevention, and evidence-based management is recommended.