Several polymerized high internal phase emulsions (polyHIPE) of various porosity but the same pore diameter were prepared. It was demonstrated that the pore size distribution of void pores and interconnecting pores is similar and it can be described by a log-normal distribution. Flow-through porosity matches closely static porosity and the non-polymerizable fraction of initial emulsion, demonstrating an open structure of polyHIPE that allows flow through the entire porous polymer. Pulse response experiments demonstrated flow uniformity. Pressure drop analysis allowed estimation of porosity effect on permeability. Fitting of experimental data with different pressure drop models revealed that interconnecting pore diameter should be used as a characteristic dimension to describe pressure drop on polyHIPE accurately. Linear correlation between permeability and flow-through porosity demonstrated that the effect of the porous polymer structure on the flow properties is independent of porosity. This finding suggests that polyHIPE hydrodynamics does not change with porosity, facilitating prediction of their performance for various applications where flow-through mode is important.