This study analyzes the influence of grain size and their distribution of the deposits in the coastal environment and the sub environments. The samples were collected from three locations on the East coast of Tamil Nadu namely Sathurangapatnam, Mahabalipuram and Nemili beach. These three locations have distinct features. This enables us to compare the coastline process and their different sedimentary deposits. The Folk and Ward (1957) equation in terms of mean, standard deviation, skewness and kurtosis was used to identify the sediment distributions in the coastal environment. The sub environments are identified by bivariate plots. In all the three locations the presence of coarser sand was very less up to the maximum value of 10%. The remaining was medium and fine sands. The fine sands are dominant in Sathurangapatnam, the medium sand is dominant in the other two locations. It reflects the wave energy fluctuation in the dynamic wave energy creation and dissipation process. During the backwash, the wave gets back the medium-sized sand and leaves the fine sand on the beach due to high energy backwash. The sediment transport rate, sediment transport capacity, cross shore profile changes and the human interventions are taken into consideration in this study. This implies that the sand beach is an erosional type of beach. Mahabalipuram beach is identified as Stable/ Accretion beach. This study is used to mitigate risks to human settlements, ecosystem, and infrastructure.