This paper investigates the durability of entrepreneurial marine protected areas (EMPAs) by exploring the role of the private sector in marine conservation. Set within a wider set of social science questions around the marine protected areas as negotiated interventions, we focus on whether and how tourism entrepreneurs can instill a long-term vision for marine conservation, funding and management, thereby overcoming commonly cited implementation and enforcement failures in state-led marine parks. The analysis is based on an empirical comparison of the Yayasan Karang Lestari coral restoration project in Pemuteran on the Northwest coast of Bali, and the marine tourism park around the island of Gili Trawangan off the west coast of Lombok in Indonesia. Our results show that the private sector is able to increase awareness of conservation amongst tourists and coastal communities, provide new income alternatives, and provide financial capacity to support marine conservation activities. It does not, however, appear to have the capacity to create durable, institutionalised arrangements without state support. These findings feed into a wider discussion on the formation of EMPAs, the role of alternative organisational structures and technologies in facilitating change in coastal areas, and how traditionally economic concepts such as entrepreneurship can contribute to a wider understanding of marine conservation governance.