Three lessepsian fish immigrants—Siganus luridus, Siganus rivulatus and Fistularia commersonii—as well as two alien macroalgae—Stypopodium schimperi and Asparagopsis taxiformis—are reported for the first time from the Messiniakos Gulf (south-east Ionian Sea, Greece). Findings of S. schimperi and A. taxiformis correspond to their westernmost records from Greek waters. Direct field observations showed that S. luridus has established a permanent population, the first to be mentioned in the Ionian Sea taken as a whole. The results increase the total number of marine aliens of the studied area to 14 species, enhancing the assumption that the south-east Ionian Sea is a hot spot on the way of lessepsian species spreading to the west.