The invasion of marine species is a threat to local and global biodiversity and can have many ecological, economic and social impacts. The bivalve Isognomon bicolor has invaded the rocky shores of Brazil and spread along the coast, occurring from Rio Grande do Norte to the Santa Catarina State. The present study evaluated the distribution of I. bicolor on different rocky shores of Arvoredo Island (Santa Catarina State) and its relationship with other taxa. A high density of I. bicolor was found on the exposed shore, which was associated with the occurrence of articulated calcareous macroalgae. In addition, I. bicolor was also found in empty shells of the barnacles Tetraclita stalactifera and Megabalanus spp. The physical structure of these habitats probably plays an important role in the success of I. bicolor invasion. For these reasons, I. bicolor evidences an alteration on the benthic community of the rocky shores and its potential consequences become a threat to local species.