Implementing densification while ensuring green space accessibility is a crucial planning challenge. The powerful role of private for-profit actors densification projects mean that green spaces are at risk of being co-opted by private interests and transformed into club goods. Using a new-institutionalist approach, we analyse the implementation of densification and urban greening based on two case-studies in Switzerland and the Netherlands. We ask what planning strategies are successful in ensuring public access to green spaces in private-led densification. To counteract club formation, planners need to restrict property rights, actively monitor implementation of planning objectives, and ensure an open physical design.