Tsunamis can cause significant damage to structures within the harbor due to the water level changes and strong currents they generate. The 6.6 Mw earthquake occurred near Samos Island on 30 October 2020 caused a tsunami due to vertical deformation of the sea floor. The tsunami caused heavy damage to the floating pontoons at Sigacik (Teos) Marina in Seferihisar. While there are numerous studies regarding the propagation of tsunamis, their run-up, and inundation distances, the damage caused by tsunami-induced water level changes and currents on floating pontoon docks with mooring chains has not been investigated yet. Numerical modeling is an important tool to calculate the loads and tensions acting on the floating structures in the time domain. In this study, dock A, which is the most damaged floating dock in Teos Marina, was numerically modeled using a midfidelity hydrodynamic model, ANSYS™ AQWA®. Initially, the stability of the floating dock was examined without the tsunami. Subsequently, the tsunami-induced water level changes and currents were introduced to the model. Displacements and rotations of the pontoons, tensions in the chains, and forces on the connections between pontoons were calculated. The safety factors for sliding and uplifting of the concrete anchorage blocks were examined and the stability conditions were checked. Results were compared with the observations of the Marina officials, eyewitnesses, captured photographs. Consequently, it was shown that chain breakages, pontoon connection failures, and the uplift of the concrete anchorage blocks could be simulated in the model.