Regarding the challenges of the twenty-first century, this study aims to explore the role of landscape architecture within the multidisciplinary setting of the studies on coastal disasters. Thus, it focuses on Istanbul, which deserves being one of the most well-known coastal megacities of the world, not only due to its long history dating back to 6700 BC but also due its unique coastal configuration. This ever-expanding but disaster-prone megacity stands on two peninsulas belonging to different continents, holds the only strait connecting the Black Sea to the other seas, and accommodates 12 lakes with more than 100 streams. These coastal features promote the vulnerability of the megacity to a wide range of natural and man-made disasters, such as earthquake, tsunami, flood, sea level rise, and salinization. The evaluation process of this study benefits from the GIS and comprises five major phases: examining the urban-landscape change, defining the major coastal disasters, identifying the disaster-prone environments, and defining multilayered landscape planning strategies. This study develops landscape planning strategies for disaster-prone coastal urban environments by deriving from the complex dynamics of the Istanbul megacity. This study is an attempt to further disaster-sensitive landscape studies in the belief that not only Istanbul but also the other coastal megacities will benefit from them.