The new occurrence of Three species of bivalves from Pinnidae family  is recorded for the first time from Palk Bay area based on a live and dead shells collected from the Intertidal area . All the three species are under the family of  Pinnidae, Pinna bicolor, Pinna deltodes and Pinna incurva . In seagrass bed of Thondi Coast, all the species of Pen shells Pinna bicolor, Pinna deltodes and Pinna incurva  were embedded in muddy sand and found associated with seagrasses at inter-tidal area. It was also found buried in hard substratum associated with living zoanthids and soft coral. The collected specimens were identified as, (1) Pinna bicolor, (2) Pinna deltodes and (3) Pinna Incurva by using both morphometric and meristic characters. The paper described the taxonomic status and the description of the three species of bivalves collected from Palk Bay areas.