Ecological restoration projects may provide solutions for degraded ecosystems in estuaries, but are challenging due to complex governance processes. Scientific studies on the latter are limited. The aim of this paper is to provide a better understanding of the governance process aiming at ecological restoration in estuaries. Based on a literature review, five success conditions for ecological restoration projects in estuaries were formulated. These conditions concern: (1) the presence of options for experimentation; (2) the use of the right communication strategies; (3) a pro-active role of key individuals; (4) sufficient project support; (5) active stakeholder and knowledge integration. These conditions were elaborated upon in a case study on the reopening of the sluices in the Dutch Haringvliet and by conducting seven expert interviews. The case study was a clear “example of failure” due to absence of several conditions. We conclude with some recommendations to enhance future ecological restoration projects.