The accurate simulation of the hydrological behavior in paddy fields is crucial considering the large percentage of area occupied by them and the amount of water resources used. Each paddy field may be considered similar to a detention pond since rice is grown under submerged conditions, where the water flows not because of the difference in elevation, but rather due to a complex waterway connecting the paddy fields. The Storm Water Management Model (SWMM), originally developed to simulate stormwater in urban areas, provides an opportunity to simulate paddy fields under these conditions. The preparation of model inputs for the simulations, however, requires considerable time and effort. A module was, therefore, developed to be operable in the QGIS software, making it convenient to prepare SWMM inputs for paddy fields. The module has two-tabbed interfaces that require vector data for paddy fields as polygons, conduits as polylines, and crossing points of conduits as points. A text file of the comma-separated value format is required for additional inputs. The other interface tab provides an opportunity to set up model options. The module was applied in a paddy field with a reservoir, which successfully generated SWMM model inputs for 723 junctions, 784 conduits, and 351 paddy fields. It was, therefore, concluded that the module can provide user convenience in the preparation of model inputs for paddy field simulations.