ABSTRACT. – Five individuals of the blunthead puffer Sphoeroides pachygaster were caught along the Algerian coast during the first quarter of 2014 and five other specimens were observed on the Mediterranean coasts of France between 1995 and 2017. These records highlight the wider spread of this thermophilic species in the Mediterranean. Until now, the Sicily Strait was considered as a central core from which the population has spread in different directions, including on French coasts. However, reports along the Algerian coasts presuppose a different dynamic, which consists of an entry via the Strait of Gibraltar of new individuals from the Atlantic. Some arguments are advanced here to support this hypothesis and to reassess the species’ biogeography in the Mediterranean Sea.