Moisture transport plays a major role in the accumulation of water and the maintenance of the ice sheet in Antarctica. Hence it is necessary to understand how moisture is transported to the Antarctic by atmospheric circulation. We discussed the characteristics and seasonal variations of air transport routes and the regions of origin of air parcels in clear and snowy weather conditions. We calculated the air transport routes to the Syowa Station (SYOWA) and Dome Fuji Station (DOME-F) for 5 days using a trajectory model and ERA-40 reanalysis data from 1990 to 1999, and we determined various backward trajectories using cloudy conditions and general weather conditions from ground-based observations. At SYOWA, in snowy condition, most of the air parcels originated in the Atlantic Ocean with eastward and upward advection. On the other hand, in clear condition, the air parcels originated in the continental interior with downward advection. A low-pressure area was found to the west of SYOWA in the troposphere under snowy conditions, suggesting that the moisture transport to SYOWA has a close association with the disturbances from the Atlantic Ocean. The trajectories traveling to DOME-F were mostly over the sea under snowy conditions in July (winter). A ridge that developed around DOME-F caused the air parcels from the Atlantic and Indian oceans to move over the continent. Under clear conditions, we found few differences in the distributions of geopotential heights. Moisture transport routes are important as they can be used to interpret ice core data in the future.