Vascular access devices play vital roles within neonatal care. We aimed to identify neonatal vascular access device insertion and management practices, and describe the incidence and risk factors for complication development. This is a prospective cohort study of neonates requiring vascular access devices over 3 months in an Australian quaternary-referral neonatal intensive care unit. In addition to describing current practices, primary outcomes were device failure, complications, and skin complications. Results are reported using descriptive statistics and with risk factors calculated via Cox proportional hazards regression. A total of 104 neonates required 302 vascular access devices, over 1375 catheter days. Peripheral intravenous catheters (PIVCs) were most used (n = 186; 62%), followed by umbilical venous catheters (n = 52; 17%). Insertion attempts were often undocumented; but for those recorded, 5% of devices (n = 15) required 4 attempts or more. Device failure occurred in 28% (n = 82), at an incidence rate of 62.5 per 1000 catheter days (95% confidence interval [CI] 49.7-75.9). Failure was most frequent in PIVCs (37%; n = 68), peripheral arterial catheters (33%; n = 2), and peripherally inserted central catheters (20%; n = 6). Infiltration and extravasation were the most frequent cause of PIVC failure (12%; n = 35). A birth weight less than 1500 g was associated with a significant decrease in PIVC failure (hazard ratio 0.58; 95% CI 0.34-0.99).