Abstract During May 2011, the symbiotic barnacles Chelonibia patula (Ranzani, 1820) was collected in Iskenderun and Mersin Bays on the Levantine coast of Turkey. Three specimens of the swimming crab Portunus segnis (Forskål, 1775) and two specimens of the blue crab Callinectes sapidus Rathbun, 1896 infested by C. patula were obtained. This is the first record of C. patula on the carapace and cheliped of P. segnis from the Turkish coasts. Besides, it was also found that within the frame of this study C. patula has expanded its distribution range on C. sapidus carapace from Iskenderun to Mersin Bay, Levantine coast of Turkey.