ABSTRACTMost of the sand dunes close to the Cuddalore coast of India have been destroyed due to human pressure. The remaining coastal sand dune (CSD) is under extreme threat due to unplanned development. The purpose of this study is to investigate the species diversity, plant communities in different morphological types, spatial-temporal changes in the distribution of sand dunes, and the state of their conservation. In the coastal dunes of Cuddalore, 25 perpendicular transects parallel to the coast were sampled. Following analysis, 105 vascular plants from 39 plant families and 85 genera were identified as part of the CSD flora. The least disturbed sites harbored more species than the heavily disturbed sites. Members of the Poaceae and Fabaceae families dominated the flora, and 68% of the species in the dunes were herbaceous. The sand dune cover is significantly reduced and fragmented in various parts of the study area, and negative changes have been observed at a rate of more than 100 ha per year between 2003 and 2020. A CSD conservation policy that ensures species succession in the form of a three-layered zone is proposed as a long-term sustainable option for preserving Cuddalore coastal flora biodiversity.