With the enactment of its ‘Basic Space Law’ in 2008, a significant shift occurred in Japan's space policy away from a narrowly circumscribed interpretation of the concept of space for ‘peaceful purposes’ to a broad understanding of space for ‘security’. Viewed in a global context, Japanese space policy appears symptomatic of a broadened and more malleable understanding of space for security purposes, as already advocated by several other leading spacefaring powers, and proponents of this understanding of space for security argue that this is consistent with international standards and the expectations of a ‘normal’ space power. By attempting to redefine understandings of ‘peace’ and ‘security’, however, the Basic Space Law and subsequent direction of Japanese space policy raise complex and ongoing issues over the interpretation of Japan's ‘Peace Constitution’. This article reviews policy and academic discussions of the recent evolution of Japanese space policy in this respect, arguing that greater emphasis on ‘security’ – understood in a deliberately broad sense in policy terms – has been key to articulating and justifying the reformulation and redirection of Japanese space policy, but that this also brings with it room for ambiguity over the exact nature of Japan's space ambitions at both national and regional levels.