This prospective crossover study compared the incidence of posterior vessel wall puncture between two approaches during ultrasound-guided simulated central venous cannulation by anaesthesiology trainees. Each phantom model, simulating a central vein and artery, was cannulated by 37 anaesthesiology trainees under ultrasound-guidance using the in-plane approach (IPA) and out-of-plane approach (OPA). Total procedural time and the time taken from starting image scanning until commencing puncture, was recorded. The number of attempts required to achieve successful venous cannulation was noted. Finally, the models were examined for posterior venous wall and arterial puncture. Total procedural time was shorter with the OPA (26.5 vs 50.3 seconds, p=0.001). The time taken from starting image scanning until commencing puncture was shorter for the OPA (2.2 vs 12.3 seconds, p