Delta is the most important depositional structure that forms at the confluence of fluvial and marine conditions. It is made up of a large amount of sediments that come from both rivers and the ocean and are deposited near the river's mouth due to the interplay of both fluvial and marine processes. Sagar Island, on India's east coast and one of the largest deltas in the Sundarban group, is threatened by coastal erosion, coastal vegetation deterioration, and a variety of natural disasters. Wave activity, clay mining, and the influence of the tidal and river currents of the Muri Ganga and Hooghly Rivers are the primary causes of erosion. Natural and human activities are causing morphological changes on Sagar Island at an alarming rate. Rapid erosion has been observed in the eastern part of the island due to the destabilization and growth of tidal flats and the gradual shifting of water current towards the island. Furthermore, Tropical cyclones, flood events, saline water intrusion, land degradation, tidal ingression, and dune encroachment are important natural environmental hazards (NEH) that harm the island. The majority of the people in the region have a low quality of living and are dissatisfied with government efforts to preserve land from the effects of climate change. This study focuses on the identification of various coastal hazards and their effects on Sagar Island, South 24 Parganas, and West Bengal, India. In an attempt to alleviate these problems, suggestions are also made for the sustainable development of the coastal environment using an integrated coastal zone management (ICZM) plan.