Inter-genogroup reassortant group A rotavirus (RVA) strains possessing a G3 VP7 gene of putative equine origin (EQL-G3) have been detected in humans since 2013. Here we report detection of EQL-G3P8 RVA strains from the Dominican Republic collected in 2014–16. Whole-gene analysis of RVA in stool specimens revealed 16 EQL-G3P8 strains, 3 of which appear to have acquired an N1 NSP1 gene from locally-circulating G9P8 strains and a novel G2P8 reassortant possessing 7 EQL-G3-associated genes and 3 genes from a locally-circulating G2P4 strain. Phylogenetic/genetic analyses of VP7 gene sequences revealed nine G3 lineages (I–IX) with newly-assigned lineage IX encompassing all reported human EQL-G3 strains along with the ancestral equine strain. VP1 and NSP2 gene phylogenies suggest that EQL-G3P8 strains were introduced into the Dominican Republic from Thailand. The emergence of EQL-G3P8 strains in the Dominican Republic and their reassortment with locally-circulating RVA could have implications for current vaccination strategies.