The effect of hydrostatic pressure on the ionic conductivities in α-PbF₂, β-PbF₂, β-Pb_1-x M_x^mF_2+(m-2)x (where M^m=Na⁺, Cd²⁺, Tb³⁺, U⁴⁺), PbSnF₄, RbSn₂F₅, LaF₃ and LaF_3-1.2 mol.% CaF₂ has been investigated in the temperature range between 300 K and 700 K for pressures up to 0.30 GPa (for β-PbF₂, PbSnF₄, RbSn₂F₅) and 0.8 GPa (for LaF₃). The activation volumes of defect formation and migration, impurity defect segregation and dissociation were determined from the effect of pressure on conductivity. Keyesí treatment based on the strain energy Zener model in Grüneisen approximation was used to estimate theoretical values of the activation volumes.