© 2021, Central Fisheries Research Inst. All rights reserved.Barnacles are common epibionts on a wide range of marine organisms, including turtles. Chelonibia testudinaria is a successful epibiotic barnacle species, and mainly turtles are responsible for their wide range dispersal. In the present study, the mitochondrial Cytochrome Oxidase I (COI) gene haplotypes of C. testudinaria from Caretta caretta hosts were evaluated. The samples were collected from three dead C. caretta turtle carapaces in 2014 from the Middle East Technical University, Institute of Marine Sciences coastline. Results were also compared with those samples submitted to databases (NCBI and BOLD-system, 139 in total). By comparison, three clades were recorded like previous studies: the Atlantic-Mediterranean clade (Clade-α), the Indian-Pacific Ocean clade (Clade-β), and Magdalena Bay (Eastern Pacific-Clade-γ) clade; all samples collected from Turkish shores clustered in the Atlantic-Mediterranean group (Clade-α). The gene flow between the three clades was deficient and highly significant (0.02, 0.03, and 0.03, respectively). According to network age estimation, present study samples’ clade (Clade-α) diverged from the Clade-β approximately 200 kya (SDs=0.22, SDy=4402.90) and Clade-γ 130 kya (SDs=0.17, SDy=3494.55). In the present study, eight haplotypes were observed in total, two of which were specific to the region.