Abstract: This is the last of three lectures about mirror symmetries for parabolic Hitchin systems. We first recall the new moduli space (associated to nilpotent orbit) we defined in the first lecture and focus on the case of the orbit being Richardson. Then, we study the geometry of Hitchin maps of this new moduli space (associated to the Richardson orbit) and of the usual moduli space (associated to the polarization of the Richardson orbit). Finally, we prove SYZ and topological mirror symmetries. This is based on the joint work with B.Wang and X. Wen (arXiv:2403.07552).