Whereas open digital platforms drive innovation in industries, platforms in primary healthcare are mostly closed. Policy-makers have been looking for ways to open up primary healthcare platforms to stimulate collaboration and innovation and need to do so even more due to the ongoing COVID-19 crisis. Yet, there is not one way of opening up platforms in primary healthcare, just as it is unclear how different ways of openness can lead to more innovation. This paper analyzes the opportunities and challenges in realizing platform openness while examining alternative forms of openness. To answer this, we (1) conceptualize different forms of platform openness (sponsor-provider-platform-user openness), (2) examine how these forms of openness can resolve barriers to innovation, and (3) examine what challenges need to be overcome to realize that form of openness in practice, such as complexity in roles, regulations, and ICT infrastructure. The findings are relevant to structure further research on how platform openness leads to more innovations in healthcare.