In Japan, Internet based learning is still at an early stage. However, adult learners in Japanese society expect the development of flexible e-learning programs. This case study examines motivational factors affecting online learning in a Japanese and Australian MBA program, using observations, interviews and a questionnaire survey. The data were investigated from motivational categories of the ARCS model (an acronym from Attention, Relevance, Confidence and Satisfaction) and influence of e-learners' learning environment, by comparing two e-learning experience stages, beginning and final. The analyses revealed that whereas the e-learners at the beginning stage were curious about e-learning, required encouragement in individual learning situations, and set goals individually, the learners with about two years e-learning experience were motivated by interdependence, flexibility and sharing the rewards with family. The study also showed motivation of adult e-learners was individually different, but was positively influenced by online collaborative interaction, in particular with peers and in group activities. Interaction in e-learning settings went beyond social activities and the simple exchange of information. This article concludes with some suggestions for improving the design of e-learning programs for Japanese students. (Contains 5 tables.)