There is an increasing proliferation of bilateral strategic partnerships in and beyond the Indo-Pacific region. Yet such a partnership between Japan and New Zealand is underexplored. The central aim of this article is to fill the gap. This article first clarifies the definition of, and then provides an analytical framework for, a ‘strategic partnership’. The article then analyses how these countries laid the foundation of their strategic partnership and how they have since built upon that foundation. In the implementation process of the strategic partnership, this article examines three elements: 1) the consolidation of their strategic partnership in official documents; 2) the institutionalisation of regular meetings; and 3) participation in defence and security exercises. Although the Japan-New Zealand strategic partnership is still in the early stages, this article argues that it has the potential to grow further given bipartisan support and positive perceptions in civil society in both countries. This article also analyses three factors that exert an impact on the development of their strategic partnership: China’s continued assertive maritime presence, the rejuvenation of the US-New Zealand bilateral relationship, and Japan and New Zealand’s ongoing commitment to the South Pacific region.