This chapter investigates the passive environmental strategies embedded in the traditional houses of Bushehr, a historic coastal city in southern Iran. Drawing on the analysis of fourteen vernacular case studies, the chapter identifies how spatial configuration, material intelligence, and orientation work together to enhance natural ventilation, solar control, and thermal comfort under hot–humid climatic conditions. Key architectural features such as central courtyards, tarmeh, shanashir, and walkable roof terraces are examined for their contribution to microclimatic regulation. The study also compares variations in typology and performance across different urban districts in Bushehr, revealing how these dwellings respond to contextual factors such as street width, wind direction, and urban density. The findings offer a transferable framework for integrating vernacular passive principles into contemporary design, especially in coastal regions seeking sustainable, low-energy architecture.