This study examines the effects of a 2-week intensive English program based on the college students' perceptions of core competencies: English Communication Competency, Self-Directed Competency, Community Competency, and Knowledge and Information Literacy Competency. The program was non-credit and was held in January 2019 for first-year students who had chosen to attend a university in Korea in the upcoming semester. The data for this case study was collected through a questionnaire completed by 33 students and reflection papers from students and was analyzed quantitatively and qualitatively. The results showed that three competencies (English Communication Competency, Self-Directed Competency, and Knowledge and Information Literacy Competency) of the participants were improved after joining the English program. The results also revealed that Community Competency did not improve significantly after joining the program but showed a strong tendency. The results indicated that a short term English program is effective in the aspects of enhancing college students' core competencies. It is necessary to continuously monitor the effects of the program in the aspects of core competencies. The pedagogical implications and future directions of the study were discussed.