Phase transitions and equations of state of the alkaline earth fluorides CaF 2 , SrF 2 , and BaF 2 were examined by static compression to pressures as high as 146 GPa. Angle-dispersive x-ray diffraction experiments were performed on polycrystalline samples in the laser-heated diamond-anvil cell. We confirmed that at pressures less than 10 GPa all three materials undergo a phase transition from the cubic ͑Fm3m͒ fluorite structure to the orthorhombic ͑Pnam͒ cotunnite-type structure. This work has characterized an additional phase transition in CaF 2 and SrF 2 : these materials were observed to transform to a hexagonal ͑P6 3 / mmc͒ Ni 2 In-type structure between 63-79 GPa and 28-29 GPa, respectively, upon laser heating. For SrF 2 , the Ni 2 In-type phase was confirmed by Rietveld refinement. Volumes were determined as a function of pressure for all high-pressure phases and fit to the third-order Birch-Murnaghan equation of state. For CaF 2 and SrF 2 , the fluorite-cotunnite transition results in a volume decrease of 8 -10 %, while the bulk modulus of the cotunnite-type phase is the same or less than that of the fluorite phase within uncertainty. For all three fluorides, the volume reduction associated with the further transition to the Ni 2 In-type phase is ϳ5%. The percentage increase in the bulk modulus ͑⌬K͒ across the transition is greater when the cation is smaller. While for BaF 2 , ⌬K is 10-30 %, ⌬K values for SrF 2 and CaF 2 are 45-65 % and 20-40 %. Although shock data for CaF 2 have been interpreted to show a transition to a highly incompressible phase above 100 GPa, this is not consistent with our static equation of state data.