Simulation data to accompany the journal article "Rheology of mobile sediment beds in laminar shear flow: effects of creep and polydispersity" by Rettinger et al. (2022) in Journal of Fluid Mechanics. The data set features the four simulation setups with varying degrees of polydispersity, denoted as mono, poly10, poly50, and poly100. Each setup has two subfolders: 'particle' and 'fluid'. The 'particle' folder contains files with particle-related quantities. The name of the file indicates the simulation time step. Each file contains seven columns of data: the x-, y-, and z-coordinate of the particle's center of mass, followed by its radius and the three translational velocity components up = (ux, uy, uz). Each row thus contains the instantaneous properties of a single particle. Additionally, the row-ordering between time steps remains the same, i.e., the x-th row always denotes the same particle. The 'fluid' folder contains files with fluid-related quantities. Again, the name denotes the simulation time step. Each file contains three columns of data: the three velocity components uf = (ux,uy,uz) of the horizontally averaged flow field. Each row corresponds to a particular vertical (z-) coordinate, denoting the height above the bottom plane. This coordinate is given in the additional file 'height.txt'. All data is given in simulation units where the lattice Boltzmann unit system is used. Updated version 1: Added a jupyter notebook (in python) that exemplifies how vertical profiles, e.g., of solid volume fraction and fluid velocity, can be extracted from the provided data. Fix in fluid height profiles (height.txt). Updated version 2: Added missing last column (z-velocity) to the particle data. Maintained consistent ordering of entries in particle data throughout all time steps.