Hikikomori—acute and severe social withdrawal, is a mental health problem worldwide. Although previous works have indirectly suggested that youth with high levels of hikikomori traits may have difficulties with various aspects of their career choices, no research has empirically investigated this. We address this gap by examining the associations between hikikomori traits and indicators of career choice (environment- and self-career exploration, outcome expectations, and exploratory career intentions) among Japanese undergraduates. A total of 756 Japanese youth participated in our online survey (79.0% women; Mage = 20.9, SD = 0.6). All participants were third-year university students who planned to enter the labor market after graduation. Correlation and path analyses consistently indicate negative associations of hikikomori traits with environment- and self-career exploration, career expectations, and intentions. These results suggest that youth with high levels of hikikomori traits experience difficulties in deciding on careers that are suitable for them in society because they tend to avoid interpersonal relationships and social participation. Based on our findings and results from prior studies, we propose the promotion of healthy identity development as a useful perspective for student counseling and career guidance.