TULIP, Turning LInac for Protontherapy, is a novel accelerator systems for protontherapy mounted on a rotating gantry designed by the TERA Foundation and CERN [1] , [2] . TULIP is natively designed with a 3D active scanning system that, besides the transverse scanning with fast magnets, features a fast beam energy variation from the linac to scan in the longitudinal direction in few ms. The main goal of this research is to characterize TULIP’s beams, through Full Monte Carlo (MC) simulations. The study combines the multi-particle tracking programs, RF Track [2] , Travel [3] , MADx-PTC [4] and the FLuka Monte-Carlo code [5] , [6] , enabling to follow each particle from the source through the linac, the beam transfer lines and the nozzle elements, until the isocenter such that transverse and longitudinal phase space characteristics are accounted for each particle. The particle fluence results in air at the isocenter and in upstream and downstream positions along the beam direction and the depth-dose curves are obtained and presented in a beamline model for a set of beam energy values and scanning magnet kick strengths. The results, suitable for characterizing in detail the beam spots for this particular accelerator system, can be used as input to generate a beam model in a commercial TPS and thus to allow the comparison with Fluka results in real patient case scenarios.