This study aims to analyze deterrents to Korean language education participation among adult immigrants who do not attend Korean language programs, and classify immigrants based on the patterns of these deterrents. It also aims to explore the characteristics of each identified immigrant group, using a newly developed Deterrents to Participation in Korean as a Second Language Scale (DPS-KSL), which was created based on previous deterrent scales, related literature, and interviews with immigrants. Data from 247 Filipino and Vietnamese immigrants were collected through surveys, and 170 usable responses were analyzed. Exploratory factor analysis identified three underlying factors: ‘negative attitudes,’ ‘social isolation,’ and ‘competing demands.’ Using these factor scores, k-means cluster analysis classified adult immigrants into five groups: ‘active young workers,’ ‘income-oriented temporary workers,’ ‘isolated long-term resisters,’ ‘integrated professional immigrants,’ and ‘married residents.’ Furthermore, the differences between the identified immigrant types for sociodemographic variables, Korean proficiency, and English proficiency were statistically analyzed, and the results were reported.