The investigation on the dipolar interactions and magnetization reversal in Ni three-Dimensional antidot arrays (3DAAs) using the first-order reversal curve (FORC) method. Ordered Ni 3DAAs were fabricated by electrochemical deposition into colloidal crystal templates of self-assembled polystyrene spheres. The samples have the same pore size of about 500 nm but different thicknesses, ranging from 0.3 μm to 1.2 μm. The FORC diagram analysis reveals a decrease in the magnetic dipolar interaction with the increasing sample thickness, as well as a decrease in the coercivity distribution. This results from the transition from the dipolar interaction to the exchange coupling as the thickness increases.