A body structure of a water-jet propulsion personal watercraft, comprises a body having an inner space defined by a hull and a deck, an engine mounted within the inner space of the body, a water jet pump placed behind the engine and configured to be driven by the engine, and a bulkhead placed behind the engine and configured to separate the inner space into an engine room on a front side within which the engine is contained, and a closed rear space on a rear side, wherein a first drain hole is provided in the closed rear space of the body so as to communicate with an outside of the watercraft.