Seoul is the first city in South Korea to provide affordable social housing, beginning in 2015. Despite the importance of studying its space, configuration, and functionality, which impact the residents’ quality of life, research on social housing in Seoul is sparse. The purpose of this study is twofold: (1) to analyze the spatial layout and utilization of social housing and (2) to compare it to the layout and utilization of public rental housing provided by Seoul Housing & Communities Corporation (SH). A total of 120 units from 30 social housing projects open to the public in Seoul were selected. This study found that social housing in Seoul primarily consists of compact housing units targeting young adults and newlywed couples, with a high proportion of diverse spatial configurations. In South Korea, while the SH specialized floor plan is commonly used as a standardized prototype in contemporary apartments, the floor plans for social housing exhibit a broader range of shapes and spatial configurations. Distinct criteria are employed for space separation in designing social housing. Separating bedrooms or kitchens may be the priority depending on the specific housing unit, resulting in multiple layouts. The results suggest that ongoing research could contribute to exploring improved approaches for region-specific social housing design and enhancing residential environments.