Rice (Oryza sativa L.) is one of the most significant cereal crops, about 3 billion people, nearly half the world's population; depend on rice for survival and it offers up to 80% of daily energy intake in most of the Asian countries. Knowledge of the distribution, extent and pattern of genetic variation is useful for estimation of any possible loss of genetic diversity and its role in breeding programs. This work assessed the genetic diversity among 25 coastal rice populations of five regions of Kerala (South India) using 18 microsatellite markers. A mean PIC value of 0.37 and an average of 3.5 alleles per loci were observed. Mean Heterozygosity value of 0.29 and gene diversity value of 0.41 was attained. AMOVA demonstrated that genetic differentiation was significant at P<0.001 and FST index value of 0.035 was obtained. Of the total diversity, 57.76% was attributed within individuals, 38.71% was attributed among individuals within populations and 3.53% among populations. Information regarding the amount of genetic variations in these salt tolerant coastal accessions and genetic relationship between genotypes are essential for designing effective breeding programs. Especially, to meet the differentiated goals of plant breeding such as breeding for increasing yield, wider adaptation, desirable quality, pest and disease resistance.