A 26-year-old man underwent laparoscopic appendicectomy for acute appendicitis that was carried out uneventfully after initial urethral catheterisation to empty the bladder. Postoperatively, he developed oliguria associated with high drain output and elevated drain fluid creatinine. A contrast-enhanced computed tomography urography scan showed a small amount of contrast in the intraperitoneal space. A diagnostic laparoscopy performed for a suspected bladder injury revealed that the drain (inserted via the suprapubic port) had traversed the bladder. The drain was removed, and the bladder defects were repaired. The catheter was removed 2 weeks later uneventfully. It is important to recognise and avoid the urinary bladder during suprapubic port insertion during laparoscopic appendicectomy. This complication can be minimised via initial bladder decompression and introduction of the suprapubic port lateral to the umbilical ligaments. A high index of suspicion is required to diagnose a small bladder injury.