Knowledge of suckling behaviour in beef calves is important for understanding the health and wellbeing of both cows and calves. The present study was conducted to explore the use of tri-axial accelerometers to identify suckling bouts and suckling duration per bout in beef calves under free-range conditions. Three experiments were conducted: Experiment 1 was conducted to develop a model to characterise suckling in calves; Experiments 2 and 3 were conducted to apply the model when cattle were managed in pastoral paddock conditions. One Holstein Friesian and one Droughtmaster cow-calf pair were used in Experiment 1 for 2 days. The tri-axial accelerometer was fitted to a neck collar of the Droughtmaster calf and at the bottom and the right side of a halter on a Holstein Friesian calf on consecutive days. The initial model was developed using data collected from one calf for one day only to classify accelerometer data into suckling and non-suckling periods. In Experiment 2, 24 Belmont Red calves with accelerometers attached on the right side of the halters were visually observed for 10 days. The model was applied to raw data obtained through use of the accelerometers and the model could be used to successfully identify 98.8% of suckling bouts when compared with visually recorded behavioural data. The average suckling duration per bout recorded by accelerometers was 9.72 ± 0.20 min, whereas visually it was 9.32 ± 0.19 min. In Experiment 3, 20 Brahman calves fitted with accelerometers were visually observed for 6 h for 3 consecutive days. The model could be used to identify 95% of suckling bouts from the accelerometer data, corresponding to total number of suckling bouts observed visually. The average suckling duration per bout recorded by accelerometers was 13.69 ± 1.82 min, while with visual observations was 12.23 ± 1.77 min. The results indicate that accelerometers are a very effective tool to record suckling behaviour in beef calves in pastoral paddock conditions.