The temperature dependence of the thermal diffusivity and thermal conductivity of the multiferroics BiFeO3, Bi0.90Sm0.10FeO3 and Bi0.90Еu0.10FeO3 is studied. It was found that the substitution of bismuth ions by the rare-earth europium and samarium ions in bismuth ferrite leads to a decrease in phonon thermal conductivity in a wide temperature range. It was established that the decrease in the thermal conductivity of bismuth ferrite is due to resonance scattering of phonons at paramagnetic levels of europium and samarium ions.