Purpose Peri-operative anticoagulation is essential in reducing thrombotic complications following open arterial surgery. In Fiji, where open arterial procedures remain the primary treatment for advanced vascular disease, there is no formal local anticoagulation protocol. This study aimed to evaluate adherence to international peri-operative anticoagulation guidelines and its relationship with clinical outcomes at Lautoka Hospital. Methods A retrospective audit was conducted at Lautoka Hospital, Fiji, including all adults who underwent open arterial surgery between January 2025 and April 2026. Adherence was assessed against ESVS and SVS recommendations using electronic medical records and drug charts. Results A total of 108 patients were included. Overall adherence to peri-operative anticoagulation guidelines was 63.0% (68/108), while 37.0% (40/108) demonstrated protocol non-adherence. Adherence rates were 83.3% pre-operatively, 71.3% intra-operatively and 90.7% post-operatively. Surgeon preference was the leading cause of non-adherence (85.0%). At least one postoperative complication occurred in 33/40 (82.5%) non-adherent patients compared with 11/68 (16.2%) adherent patients. This association was statistically significant (x² = 43.18, p < 0.001). Protocol non-adherence was associated with increased odds of postoperative complications (OR 24.4, 95% CI 8.63-69.12). Following establishment of a vascular unit, overall adherence improved from 8.5% to 89.0%. Conclusion Peri-operative anticoagulation practices at Lautoka Hospital demonstrated moderate overall adherence to international guidelines, with most deviations attributable to practice variation. The establishment of a dedicated vascular unit was associated with significant improvement in protocol adherence. Development of standardized local anticoagulation protocols may further improve patient outcomes and enhance the quality of vascular care in Fiji.