Abstract. The off-line FLEXible PARTicle stochastic dispersion model (FLEXPART) is nowadays a community model used by many scientists. Here, an alternative FLEXPART model version has been developed, tailored to use with the meteorological output data generated by the CMIP5-version of the Norwegian Earth System Model (NorESM1-M). The atmospheric component of NorESM1-M is based on the Community Atmosphere Model (CAM4), hence this FLEXPART version could be widely applicable and it provides a new advanced tool to directly analyse and diagnose atmospheric transport properties of the state-of-the-art climate model NorESM in a reliable way. The adaptation of FLEXPART to NorESM required new routines to read meteorological fields, new post-processing routines to obtain the vertical velocity in the FLEXPART coordinate system and other changes. These are described in detail here. To validate the model, several tests were performed that offered the possibility to investigate some aspects of off-line global dispersion modelling. First, a comprehensive comparison was made between the tracer-transport from several point sources around the globe calculated on-line by the transport scheme embedded in CAM4 and the FLEXPART model applied off-line on output data. The comparison allowed investigating several aspects of the transport schemes including: the approximation introduced by using an off-line dispersion model with the need to transform the vertical coordinate system, the influence on the model results of the sub-grid scale parameterizations of convection and boundary layer height and the possible advantage entailed in using a numerically non-diffusive Lagrangian particle solver. Subsequently, a comparison between the reference FLEXPART model and the FLEXPART-NorESM/CAM version was performed to compare the well-mixed state of the atmosphere in a one-year global simulation. The two model versions use different methods to obtain the vertical velocity but no significant difference in the results was found. However, for both model versions there was some degradation in the well-mixed state after one-year of simulation. Finally, the capability of the new combined modelling system in producing realistic backward in time transport statistics was evaluated calculating the average footprint over a five-year period for several measurement locations and by comparing the results with those obtained with the reference FLEXPART model driven by re-analysis fields. This comparison confirmed the effectiveness of the combined modelling system FLEXPART with NorESM in producing realistic transport statistics.