There has been much debate about the motivations and ramifications of Japanese Prime Minister Shinzo Abe’s desire for Japan to play a more proactive role in strategic affairs in Southeast Asia. The paper argues that the desire to do so stems from a broadening of Japan’s interests in East Asia from one of merely defending Japanese administration and control over what Tokyo calls the Senkaku Islands in the East China Sea to concern about the future of the maritime and strategic order in East Asia more generally vis-à-vis China’s rise. In this context, the Abe administration views the limiting of Chinese assertive actions in Southeast Asia as critical to Tokyo’s own national interests – a direction in Japanese policy that is widely welcomed by most countries in Southeast Asia due to the their concerns about Chinese behavior in the South China Sea. The paper then goes on to examine the still considerable legal, domestic and economic constraints when it comes to Japan playing a broader strategic role in Southeast Asia. In doing so, it argues that the greatest areas of impact Japan might have will be through using its weight in multilateral forums to balance Chinese influence, and as an exporter of military technology and hardware to Southeast Asian countries who are similarly concerned about Chinese behavior in the region and disruption to the post-World War Two East Asian order.