The Sundarbans mangrove ecosystems of Bangladesh’s south-west coastal region are extremely vulnerable to climate change and its impacts particularly salinity increase. Hence. the main aim of this study is to evaluate the impacts of salinity increase on the Sundarbans mangrove ecosystems at different scales (i.e., mangrove vegetation and Royal Bengal Tiger habitat) and on the adjacent coastal communities for identifying target oriented measures to adapt to salinization. To achieve this aim, we have used a multidisciplinary research framework where both qualitative and quantitative approaches are combined. The study reveals that global climate change, regional hydrological modifications and local socio-economic shifts are the major processes associated with rapid salinization across the south-west coastal region of Bangladesh. Salinity increase and its range of processes are not only contributing to reduce world’s largest and last remaining tract of mangrove’s (i.e., Sundarbans) biodiversity, but also degrade quality tiger-habitat requirements (through, for example, availability of fresh drinking water, sufficient prey population and diverse vegetative cover). Furthermore, intensification in salinity across the south-west coast of Bangladesh has become an extensive threat for human health and livelihoods. Further changes in salinity and its range of processes will make future efforts to protect and manage these diverse ecosystems more intricate. Therefore, target oriented adaptation pathways have been developed to cope with and to enhance resilience to salinization. Thus the study provides novel insights for effective and target oriented large-scale adaptation planning in the studied region.