Background Ureterosciatic hernia is a rare pelvic hernia involving the protrusion of the ureter through the greater or lesser sciatic foramen, which may result in ureteric obstruction with complications such as sepsis. Diagnosis is made radiologically by the characteristic ‘curlicue sign’. Owing to its rarity, there is no standardised management guideline, but various surgical approaches have been described. Case Presentation We report the first Australian case of ureterosciatic hernia in a female octogenarian who presented with a three-day history of left-sided renal colic, nausea and vomiting. The contrast-enhanced CT demonstrated left hydroureteronephrosis with herniation of the distal ureter through the left greater sciatic foramen. The patient deteriorated rapidly, developing septic shock, metabolic acidosis and AKI. Urgent percutaneous nephrostomy was performed for decompression, and she required intensive care unit admission for vasopressor support in the setting of E. coli bacteraemia. Following clinical stabilisation, an antegrade ureteric stent was inserted via the nephrostomy, resulting in radiological reduction of the hernia. She was discharged with a plan for regular ureteric stent exchanges and remains asymptomatic with no further hospitalisations. Discussion Ureterosciatic hernia is a rare but potentially life-threatening cause of obstructive uropathy. Initial management should involve prompt decompression with either percutaneous nephrostomy or ureteric stenting, particularly in unstable patients. Definitive management strategies in the literature include open, laparoscopic, or robotic hernia repair and ureteric reimplantation. Regular ureteric stent exchange is a well-documented alternative for those in whom major surgery is undesirable. Conclusion Early diagnosis of ureterosciatic hernia and urgent decompression are critical in the setting of sepsis. Long-term ureteric stenting may be an appropriate strategy when a major surgery is not preferred.