This article uses the lens of the Multiple Streams Approach to explore whether the agendas set by political actors in Vietnam converged with the agenda set in the Mekong Delta Plan (MDP). The MDP presents policy choices for the development of the Vietnamese Mekong Delta. The plan offers economically attractive, climate adaptive and environmentally sustainable paths forward in the face of climate change and economic uncertainties. We collected our data using qualitative techniques, including a literature review and interviews. We found convergence between the MDP’s agenda and political actors’ agendas, though divergences were also detected. Between the delivery of the MDP in 2013 and formal endorsement of its ideas in 2017, the problem stream, policy stream and politics stream were brought together by the actions of “policy entrepreneurs” (scientists and experts). Our findings suggest that agenda-setting and convergence were a crucial step towards endorsement of the strategic delta planning process for the Mekong Delta. Further research could explore issues of power mobilization in enabling or constraining decision-making. © 2019, © 2019 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.