As climate change intensifies, architects and other design professionals are creating bold visions for future dwellings, such as green buildings, masterplanned eco-cities, and even planetary-scale sustainability measures. These climatopias, categorically different from ecological utopias of the past, are architectural and urban planning proposals for the built environment that seek to address climate adaptation and/or mitigation through new design, material and sociopolitical processes. Even if never implemented, climatopias have inspired provocative thinking for the climate crisis, and they could transform systems that no longer serve the greater good. However, as with all utopian works, climatopias have the potential to do as much harm as good. Integrating research from architectural studies, utopian studies, and adaptation science, this paper defines the concept of climatopia and analyzes eight climatopia projects around the world for their effectiveness, justice, and feasibility. Our findings reveal that climatopias have the potential to support climate resilience in planning and design schemes for the built environment when they 1) employ design, construction, and material production processes that significantly lower a project’s embodied and operational carbon, 2) are affordable and involve residents in the design and implementation processes, and 3) are designed to be built and deployed today or are designed to provoke transformational thinking about potential climate solutions. To ignore these factors runs the risk of climatopias becoming yet another chapter of failed, if not harmful, utopian experiments in the built environment.