  The refraction of space-time (ST) wave packets at planar interfaces between
non-dispersive, homogeneous, isotropic dielectrics exhibit fascinating
phenomena, even at normal incidence. Examples of such refractive phenomena
include group-velocity invariance across the interface, anomalous refraction,
and group-velocity inversion. Crucial differences emerge at oblique incidence
with respect to the results established at normal incidence. For example, the
group velocity of the refracted ST wave packet can be tuned simply by changing
the angle of incidence. In paper (III) of this sequence, we present
experimental verification of the refractive phenomena exhibited by ST wave
packets at oblique incidence that were predicted in paper (I). We also examine
a proposal for 'blind synchronization' whereby identical ST wave packets arrive
simultaneously at different receivers without \textit{a priori} knowledge of
their locations except that they are all located at the same depth beyond an
interface between two media. A first proof-of-principle experimental
demonstration of this effect is provided.
