The North Anatolian Fault in the northern Aegean Sea triggers frequent earthquakes of magnitude up to <i>M<sub>w</sub></i> ∼ 7. This seismicity can be a source of modest tsunamis for the surrounding coastlines with less than 50 cm height according to numerical modelling and analysis of tsunami deposits. However, other tsunami sources may be involved, like submarine landslides. We assess the severity of this potential hazard by performing numerical simulations of tsunami generation and propagation from a Holocene landslide (1.85 km<sup>3</sup> in volume) identified off Thasos island. We use a model coupling the simulation of the submarine landslide, assimilated to a granular flow, to the propagation of the tsunami wave. The results of these simulations show that a tsunami wave of water height between 1.10 m and 1.65 m reaches the coastline at Alexandroupolis (58.000 inhabitants) one hour after the triggering of the landslide. In the same way, tsunamis waves of water height between 0.80 m and 2.00 m reach the coastline of the Athos peninsula 9 min after the triggering of the landslide. Landslide tsunamis should not be neglected as a potential source of tsunami in the area. Despite numerous earthquakes of <i>M<sub>w</sub></i> > 7 and strong detrital input (on the order of 30 cm ka<sup>−1</sup>), only a few Holocene landslides have been recognized so far, asking the question of the relationships between seismicity and landslide frequency in the area.