Over the past decade, the Japanese government and Japanese universities have increased student mobility, both inbound and outbound, to accelerate the internationalization of higher education. However, student mobility was halted in early 2020 because of the COVID-19 pandemic, and international students who had planned to engage in a traditional study abroad program could not enter Japan. The current study examined whether the unexpected implementation of online distance classes because of the pandemic affected the learning strategies of graduate students, including international students. In addition, we investigated whether the online courses functioned as an alternative to face-to-face classes. An analysis using structural equation modeling revealed that the period of enrollment, self-regulation, and country of residence were factors that influenced help-seeking behavior. Graduate students who had enrolled before the pandemic and already experienced face-to-face classes were more likely to actively seek help from instructors and classmates in online classes. Furthermore, graduate students who were unable to enter the country but were taking classes online also tended to actively engage in help-seeking from their instructors and classmates. Students' experiences of the sudden change to distance learning suggest that, to ensure a sustainable teaching and learning environment in various contexts, instructors should use class designs that consider distance learning, particularly designs that enhance students' help-seeking, even under normal circumstances. In addition, ensuring sufficient online/virtual spaces for communication among teachers and students is important.