Amid the recent intensification of global competition to secure talent, it has become necessary to grasp the international mobility trends of newly minted domestic PhD holders. The overseas-relocation plans of Korean PhD holders differ by field of study: science and engineering fields maintain a relatively high share, whereas non-science-and-engineering fields tend to maintain a comparatively low share or to see it decline. The reasons for relocating abroad likewise differ clearly by field—postdoctoral research accounts for an overwhelming share in the science and engineering fields, while remaining at a relatively low level in the non-science-and-engineering fields. These findings suggest that policies to prevent brain drain need to be designed not only around differentiated strategies that reflect the characteristics of each field of study, but also in a direction that expands domestic postdoctoral opportunities and encourages PhD holders to return home after gaining experience abroad.