Discrete dislocation dynamics (DDP) is an effective approach for probing plasticity at the micro scale. It presents a high-resolution picture of dislocation activity with details that are difficult to capture using a continuum model; it has the ability to reach experimental length and time scales, which can be challenging for atomistic modelling. To date, the utilization of DDP in nanoindentation is still limited, especially in body-centred cubic (bcc) material. This talk presents DDP simulation of nanoindentation experiment on bcc iron. Dislocation features observed experimentally under different indentation directions were reproduced, such as the formation of ‘X’-shaped dislocation transportation channels under (110) indentation [1] and the emission of prismatic dislocation loops under (111) indentation [2]. These results help interpret the observations in a nanoindentation experiment and contribute to the mechanistic understanding of incipient plasticity in nanoindentation. Further, large-scale simulation of (001) indentation was performed and compared to the experiment. The residual strain fields measured by HR-EBSD under (001) and (110) indentation were fairly well captured with DDP simulation.