Dataset contains 3D synthetic seismic waveforms for axisymmetric global Earth velocity models. The waveforms were calculated using the finite difference approach with the PSVAxi algorithm (Jahnke, G et al., 2008. doi:10.1111/j.1365-246X.2008.03744.x). The Earthmodels are 1D and use PREM parameters except close to the core-mantle boundary (CMB) where 3D ultra-low velocity zones (ULVZs) are added to the PREM background model. ULVZ are thin layers of strongly reduced seismic velocities located at the CMB that have been observed in several regions of the Earth. The dataset models interaction of the seismic wavefield with ULVZ structure with varying elastic parameters (P-wave, S-wave velocity, density), location (location at source or receiver side along the great circle path), ULVZ length, shape (box, Gaussian, trapezoid) and height. Detailed description of the approach and the model space are given in Vanacore et al, (2016). Data format is SAC (Seismic Analysis Code). Vanacore, E.A., Rost, S., Thorne, M.S., 2016. Ultralow-velocity zone geometries resolved by multidimensional waveform modelling. Geophys. J. Int. 206, 659–674. doi:10.1093/gji/ggw114