In Japan, where the shortage of care workers poses a challenge to the sustainability of the long-term care system, foreign care workers play a crucial role. This study aimed to identify the needs and challenges of Vietnamese Technical Intern Training candidates, the largest group of foreign care workers, to facilitate program reforms and a more efficient recruitment process. A semi-structured interview survey was conducted with 27 candidates in Vietnam. Interview items included reasons for choosing the training program in Japan, the desired length of stay, expectations, and career advancement after returning home. Descriptive statistics and K-means clustering were used to analyze the data. Survey results showed that all participants independently decided to pursue care worker training in Japan; 44% had considered other countries; most wanted to stay in Japan for as long as possible; and 37% wanted to live in Japan permanently. The K-means method revealed three clusters: a Japanophile cluster (preferred Japan for its landscape, culture, and national character); a word-of-mouth cluster (influenced by personal referrals); and an intellectual cluster (influenced by Japan’s economic development and care levels). Our findings indicate that support for obtaining qualifications, Japanese language skills, and caregiving skills are important to secure the stability of foreign care workers. It is necessary to tailor recruitment, training, and support for each cluster.