Lattice Boltzmann methods (LBM) are an effective upcoming approach to study fluid dynamics and thermodynamics in environmental sciences. Recent cryospheric applications include snow crystal growth in clouds and the transport properties of polar firn. The methods are well suited to study the permeability of complex heterogeneous porous media. Here we apply LBM to study the fluid permeability of sea ice, a property not well understood and difficult to determine by observation. Combining structure-preserving field sampling with nondestructive synchrotron-based microtomography, we have assembled an extensive dataset of three-dimensional tomographic images of young sea ice. This imaging method for sea ice has an unprecedented resolution (voxel size of ≈5–10 μm) and is well suited for LBM studies of our samples of approximately 1.5 cm diameter and height. We shall present first results of sea-ice permeabilities obtained by LBM simulations.