Over the past 15 years, Brussels’s partnership with Tokyo has become more goal-oriented and has acquired a certain strategic dimension. EU and Japanese leaders, along with many observers, admit that so far the potential for bilateral co-operation continues to exceed the achievements. This chapter examines the evolving EU–Japan strategic partnership, focusing on the relationship’s politico-security dimension. The discussion explores the motivations of both sides to strengthen ties, the factors that improve and inhibit co-operation and the main joint initiatives and policies. ‘New’ opportunities for co-operation are found to have emerged, in particular in the maritime security domain, while some of the ‘old’ constraints have receded, such as those associated with Japan’s international security role, and the EU’s approach to Asia beyond the ‘China only’ dimension. The geopolitical environment of both Europe and the Asia-Pacific is also undergoing major shifts, and longstanding structural limitations affecting the roles of the EU and Japan in each other’s neighbourhoods persist. All this suggests that the search for a more effective and genuinely strategic partnership is positioned to continue, while the outcome remains more, rather than less, uncertain.