In recent years, the number of foreign tourists visiting Japan has increased. However, Japan is prone to natural disasters, such as earthquakes and tsunamis, as well as river flooding caused by typhoons and heavy rains. When such natural disasters occur, foreign tourists visiting Japan may suffer serious harm because of a lack of language proficiency and information on how to respond. This paper proposes a tourism and disaster prevention information portal site to enable foreign tourists visiting Japan to have a safe and enjoyable sightseeing trip. This portal site allows users to search for sightseeing trip plans in Japan, learn disaster prevention knowledge to deal with natural disasters in Japan, and obtain multilingual smartphone apps with guidance for actions to take for disaster prevention during sightseeing trips. In this study, the author and students at Yamato University and Iwate Prefectural University built a prototype tourism and disaster prevention information portal site for foreign tourists visiting the 2025 Osaka World Expo. In the future, we will conduct evaluation experiments on this portal site and use them to improve it and build a more ideal system.