This Collective Article includes records of 29 alien and cryptogenic species in the Mediterranean Sea, belonging to eight Phyla (Rhodophyta, Ochrophyta, Cnidaria, Annelida, Mollusca, Arthropoda, Echinodermata, and Chordata) and coming from 11 countries.Notes published here can be divided into three different categories: occupancy estimation for wide areas, new records for theMediterranean Sea, and new records of species expanding within the Mediterranean Sea. The first category includes a visual surveyheld along the coastline of Peloponnese (Greece), which yielded records of 15 species. The second category includes the firstMediterranean records of the Coho salmon Oncorhynchus kisutch (Greece) and of the Arabian monocle bream Scolopsis ghanam(Tunisia). The third category includes new records for countries (Ganonema farinosum in Malta, Cassiopea andromeda in Libya,Cingulina isseli in Greece, Okenia picoensis in Italy, Callinectes sapidus in Slovenia, Charybdis cf. hellerii in Malta, Urocaridellapulchella in Cyprus, Ablennes hians and Aluterus monoceros in Lebanon, and Fistularia petimba in Greece and Lebanon), newrecords for MSFD areas or regional seas (Septifer cumingii in the Greek Ionian Sea and F. petimba in the Marmara Sea), andconfirmation of old, doubtful, or spurious records/statements (Branchiomma luctuosum in Tunisia, Thalamita poissonii in theSaronikos Gulf, and Pterois miles in Albania). Noteworthy, the three new records of F. petimba suggest that it may soon spreadfurther in the Mediterranean Sea, as already happened for its congeneric Fistularia commersonii. Distributional data reportedhere will help tracing colonization routes of alien species in the basin and may facilitate the development of mitigation measures
