Background Plate fixation is an established method for treating unstable distal clavicle fractures. However, the appropriate timing of surgery for acute distal clavicle fractures remains unclear. The present study aimed to evaluate the clinical outcomes of osteosynthesis using a Scorpion plate and to assess the influence of surgery timing on the surgical outcomes for acute unstable distal clavicle fractures. Methods We retrospectively reviewed 105 patients who underwent fixation for acute unstable distal clavicle fractures (Neer type II and V) using the Scorpion plate between 2008 and 2018. Patients were divided into early (45 patients) and delayed (60 patients) treatment groups based on the timing of the surgical intervention (within or after seven days). The outcomes were postoperative complications (nonunion, peri-implant fracture, plate loosening, plate-related pain, and stiffness). We evaluated the outcomes from X-ray radiographs and clinical notes. Results Among the 105 patients, nonunion, plate loosening, plate-related pain, and stiffness were observed in six patients (5.7%), four patients (3.8%), seven patients (6.7%), and one patient (1.0%), respectively. The nonunion rate was significantly higher in the delayed treatment group than that in the early treatment group (P=0.036). Although the difference was not significant, plate loosening and stiffness were only observed in the delayed treatment group. Conclusion Our results demonstrated that osteosynthesis using Scorpion plates achieved satisfactory surgical outcomes for unstable distal clavicle fractures . In addition, this study suggested that performing surgery within six days after injury is recommended to reduce postoperative complications .