An ankle dislocation without an accompanying fracture is extremely rare, and an open ankle dislocation is even rarer. Due to its rarity, there is no consensus on the optimal treatment strategy. A professional basketball player (a 28-year-old male) incurred an open ankle dislocation (with no accompanying fracture) during a basketball game due to plantar flexion and inversion of his ankle during the transition from dashing to stop motion. The same day, an emergency reduction under spinal anesthesia was performed with primary closure of the wound. Considering the complications of infection and decreased ankle range of motion (ROM), primary ligament repair was not performed. He was treated conservatively with cast immobilization for four weeks, and early weight-bearing and ROM exercises were initiated. At six weeks postoperatively, stress radiography did not reveal ankle instability. After three months of conservative treatment, the patient was able to play basketball at his previous performance level. Four weeks of cast immobilization without ligament repair plus early rehabilitation with weight-bearing and ROM exercises allowed for an early return without complications. Even in high-level athletes, open ankle dislocation without an accompanying fracture can be treated adequately with conservative therapy.