AbstractBivalves of the family Teredinidae are among the most destructive wood-boring species in the sea. We report the first occurrences of the warm-water shipworm Teredo bartschi in Mersin, Turkey, and Olhão, Portugal. The colonisation of the site in Mersin is likely to have occurred by rafting adults originating from the Red Sea, which passed through the Suez Canal (lessepsian migrants). T. bartschi might have been introduced in Olhão Harbour, Portugal, either by rafting adults with larvae transported by currents or by larvae transported by ships in ballast water. These seem to be the first published records of established T. bartschi populations in the Mediterranean and in northeast Atlantic.