The purpose of this study was to clarify coaches’ competencies (COM) regarding dual-career (DC) support for student athletes in Japan. The questionnaire survey was conducted at 31 universities with an online survey URL that was distributed to 300 collegiate athletic coaches. In total, there were 152 respondents (female, 19; male, 133; mean age, 43.15 ± 12.07 years; coaching experience, 12.83 ± 9.72 years). The online survey adopted a Japanese-translated version of the Dual-Career Competency Questionnaire (DCCQ), which has been translated into nine languages and is widely used in European counties. The scale consists of six factors and 33 items, each rated on a five-point scale of importance (IM) and possession (PO). The Japanese version of the DCCQ was validated through a confirmatory factor analysis, and the internal consistency of the items was confirmed by calculating the Cronbach’s alpha coefficient. In addition, we examined differences between the IM and PO for DC support by t-tests and by calculating effect sizes. The validity and reliability of the Japanese version of the DCCQ were confirmed based on the goodness-of-fit index and Cronbach’s alpha coefficients, respectively. Our examination of the differences between IM and PO in DC support revealed that coaches perceived the importance of DC support but did not possess the necessary COM to offer DC support. That finding was similar to those of previous European studies. In particular, the Japanese coaches who participated in our online survey recognized the importance of COM in terms of “collaboration with various stakeholders and departments” for DC support but did not feel as though they held sufficient COM in that regard. In other words, the improvement of DC support requires the development of a coaching program that fosters COM to work with various stakeholders. This key insight provides a direction and specific focus for programs to improve coaches’ DC support for student athletes.