The ionic conductivity and permittivity of BaR2F8 (R = rare earth element) single crystals with monoclinic BaTm2F8 structure (space group C2/m) were measured in the temperature range from 300 to 700 K. A pronounced anisotropy of ionic conductivity and a slight anisotropy of permittivity are found. The fastest ionic transport with the lowest activation energy (similar to 0.56 eV) and the highest value of the permittivity are observed along the a axis. The minimum values of conductivity with the activation energy of 0.75-0.8 eV are observed along the c axis (e.g. the axis normal to the cleavage plane). The mechanism of the ionic transport in BaTm2F8 structure is discussed.