Deltaic environments are one of the most susceptible areas to environmental degradation, urbanization, and climate change due to intricate hydrological and ecological processes. The aim of this study is to investigate and synthesize interdisciplinary planning and design strategies that enhance the sustainability and resilience of urban environments in deltaic regions through critical analysis of global case studies and nature-based solutions. The review integrates literature on climate-resilient planning integrated into urban master plans, highlighting especially nature-based solutions like sponge city concepts, green corridors, and elevated settlements. Based on international case studies such as the Ganges–Brahmaputra, Mekong, and Rotterdam deltas, the review emphasizes the integration of planning and adaptive design to increase resilience to floods, sea-level rise, and socio-economic stressors. In a design-based perspective, the research assesses the effectiveness, scalability, and local relevance of such strategies, drawing lessons for future interdisciplinarity among architects, planners, and policymakers. The results highlight locally based yet worldwide informed planning strategies to promote sustainability and habitability in future deltaic cities.