This article explores the Asia–Europe Parliamentary Partnership (ASEP), which is the parliamentary dimension of the Asia–Europe Meeting (ASEM), from the perspective of the National Diet of Japan. ASEP brings together Japan’s key neighbours and trade partners, including the European Union, its so-called natural partner with whom it shares common values. This article argues that the Japanese Diet members perform a three-level norm promotion process at ASEP. First, they promote the norms and agenda of the Japanese government and thus their activity mirrors Japan’s policies on EU, ASEM and global issues. Even the same challenges, for example the untapped partnership with Europe, are visible. Second, they drive their own personal or party agendas, demonstrating that parliamentarians are not merely mouthpieces of the government but bring plurality and even dissonance to Japan’s message. Third, they promote parliamentary empowerment and participation in international affairs, norms that facilitate the Diet Members’ ability to oversee the Asia–Europe agenda as well as empower other participating parliaments. By taking the perspective of one country, this article provides insights to the little known workings of the Asia–Europe Parliamentary Partnership.