Transit-oriented development (TOD) pursues sustainable urban development through compact growth, mixed-use zoning, and pedestrian-friendly neighborhood design in cooperation with transportation planning. Seoul has actively developed urban rail transit since the 1970s based on a TOD concept, and each station’s areas have differently evolved throughout the history of urbanization in Seoul. In response to investigating the complications of current TOD, this paper evaluates TOD characteristics through accessibility and clustering analysis methods and categorizes TOD types using the targeted 246 subway station areas at the neighborhood level. As a result, subway TODs are grouped into the four distinct categories of (1) high-density: a form of mainly mixed-use with residential and retail development and good accessibility; (2) moderate-density: average accessibility and high-mixed use; (3) compact business district setting: highly accessible to offices and retail; and (4) compact housing: high-rise apartments with schools and retail. The results also find that Cluster 2 is the most common TOD type and redevelopment possibility in Seoul, with relatively lower ranks in the building floor area (GFA) and diversity in comparison to other TOD contexts. Cluster 3 has the most significant transit demand, generating an active transit environment in Seoul. Different urban development periods impact the characteristics of TOD types.