Regionalism, an approach adopted by architects during the late twentieth century, has new relevance and potential urgency in the twenty-first century as a system for detecting and formulating the architectural language of environmental transformation in tropical cities. Historians, critics and theorists since the 1980s have contributed to a discourse that relates regionalism to vernacular conventions in architecture and describes location-specific interactions between architects and modern architecture. In contrast, for architects practising in South Asia today, regionalism offers fresh opportunities for addressing the spatial operations, material configurations and climatic strategies that best structure and amplify the quality of life in rapidly growing cities in Asia. Referencing the design of housing in Dhaka during the last decade as a case study, this paper explores how, through regionalism, architects speculate about new forms of urban life in Asian cities. It shows how contemporary architects in Dhaka engage an evolving conceptualisation of regionalism alongside the historic legacies of vernacular architecture and the disciplinary frameworks created in Bangladesh during the 1970s. This paper argues that while addressing the local realities of materials, environment and urbanisation in Dhaka today, architects also engage global thematics such as the aesthetics of atmosphere and “the unfinished” in architectural projects where regionalism manifests as speculation.