The present study was carried out in order to study the textural characteristics of sediments, and their seasonal changes along with the Coleroon estuary. Samplings were done at different stations during two seasons from monsoon of 2009 to postmonsoon of 2010. Granulometric studies reveals that the grain size parameters at different Coleroon estuary locations. The differences between the seasons were larger than those between the geomorphological units. During the monsoon the mean size was medium to fine, sorting was moderately sorted to moderately well sorted in nature, and the distribution was more positively skewed. The major part of the sediment fall in a medium to fine grained category. with respect to spatial distribution sand is dominating in the upper estuarine region i.e. up to the station 7 silt, clay are mostly enriched in lower part of the estuary. Based on the CM pattern the sediment fall in rolling and suspension field.