The tsunami following the 2011 off the Pacific Coast of Tohoku Earthquake devastated ports in the Tohoku and Kanto regions of Japan. Even Iwate Prefecture in Tohoku, which had experienced many tsunami disasters and prepared tsunami disaster mitigation measures, incurred great devastation because the tsunami was both higher than any historically recorded tsunamis and than any estimated tsunamis for disaster management. The tsunami-induced inundation destroyed many of wooden houses widely found in the area. Many ships and boats at sea were displaced by the tsunami, with some vessels colliding with others and port facilities such as cargo handling equipment and quay walls being damaged. Much debris was generated and disrupted rescue and restoration activities in the disaster aftermath. Port devastation caused stagnation in logistics and industrial operations, negatively impacting on residents’ lives and industrial activities in the disaster aftermath. There was a positive lesson that breakwaters and seawalls damaged by the tsunami reduced tsunami impacts behind them. Ports should be robust and resilient against possible tsunami hazards, considering measures for worst-case earthquake and tsunami scenarios.