We derived formulas for the tomographic resolution limits of diffraction data. Resolution limits exhibited that diffractions can provide twice or more the tomographic resolution of specular reflections and therefore led to more accurate reconstructions of velocities between layers. Numerical simulations supported this claim in which the tomogram inverted from diffraction data was noticeably more resolved compared to that inverted from specular data. The specular synthetics were generated by sources on the surface, and the diffraction data were generated by buried diffractors. However, this advantage is nullified if the intensity and signal-to-noise ratio of the diffractions are much less than those of the pervasive specular reflections.