The Javan rhinoceros (Rhinoceros sondaicus) was historically found across a large proportion of Asia from Java to northeast India. By the 1990s, it was restricted to only two locations: Ujung Kulon National Park in Indonesia and what is now Cat Tien National Park in Vietnam. These two populations took vastly different trajectories over the last 30 years, with the Indonesia population growing and the Vietnam population becoming extirpated. The conservation actions taken for both populations and the species’ conservation needs are presented. The 85 years of conservation action in Ujung Kulon is undoubtedly the reason why the species remains extant today and must be viewed as a major conservation success. Conservation efforts have included rhino protection, habitat management and community outreach. Protection efforts require intensification and population management and genetic recovery need to be included in future conservation efforts. Despite the likelihood of survival of the two populations being different in the 1990s and the various differences between their situations, important commonalities between the two case studies are identified creating lessons that must be applied to the surviving population to ensure it does not follow the same path as the Vietnam population. These include a focus on in situ conservation efforts at the expense of the riskier, but critical population management needs, local political desires being put before national and species-level conservation needs, the need to act with uncertain data, and weak community support for Javan rhino conservation. Crucially, both past and current conservation actions for the Javan rhino have lacked the scale, ambition, and pace to match the conservation needs. Taking bolder and quicker decisions is needed which would be facilitated by the establishment of a holistic, multistakeholder Javan rhino recovery program in Indonesia with strong, national leadership and sufficient funding for its implementation, something that is possible given that the responsibility for the conservation of the species falls under the central government.