The propagation characteristics of magnetostatic volume waves (MSVWs), namely, magnetostatic forward volume waves (MSFVWs) and magnetostatic backward volume waves (MSBVWs), in one-dimensional (1-D) magnonic crystals (MCs) with oblique incidence are reported. The theoretical approach based on Walker's equation was used to analyze the bandgaps associated with the MSVWs. Experiments were conducted on a 1-D MC with periodic structure in YIG layer thickness to measure the bandgaps in the MSFVWs and the MSBVWs with the incident angles at 0, 14, and 25 degrees, and at 1650 and 1385 Oe bias magnetic fields, respectively. An excellent agreement between the measured and the calculated results was achieved.