This paper discusses how Tactical Urbanism aligns with the principles of the ‘open city’ framework. The ‘open city’ is often theorised as the urban condition that best welcomes diverse and flexible use of a city’s public spaces. However, the nature of the planning system at its core is to control and predict urban development, thereby effectively reinforcing the principle of a ‘closed city’ with more fixed and rigid forms. One counter-reaction to the ‘closed city’ is the Tactical Urbanism movement, which applies principles of simple, low-cost, and often temporary public space interventions to achieve and accelerate change. Such interventions can create more ‘open’ and inclusive urban environments, enabling diversity and flexibility. However, Tactical Urbanism is applied in multiple forms by different actors with varying intentions and goals. In this paper, I question the role of Tactical Urbanism in congruence with the theoretical framework of the ‘open (and vibrant) city’, drawing attention to how tactical interventions are used to brand new development projects. Doing so, I ask if Tactical Urbanism can be (mis)used merely as ‘temporary temporariness’ to serve top-down planning strategies, resulting in the ‘closed city’.