Japan–NATO co-operation has come a long way from the initial political contacts of the 1990s, with Japan’s contribution to reconstruction efforts in Afghanistan a core factor in the development of the partnership. Alessio Patalano, however, argues that it is the counter-piracy operation in the Gulf of Aden and the Indian Ocean which has been critical to the development of a more robust form of military interaction and has set the foundations for an enhanced partnership. He explains why maritime security can continue to play a central role in driving co-operation forward, notwithstanding the need for both actors to respond to the return of peer competition at sea.