Tsunamis could cause devastating damage to vast coastal areas. In order to understand tsunami hazards in a certain area, it is important to assess the potential casualties that can result from a given event. Although many studies related to tsunami casualty estimations exist, most of them have not taken detailed evacuation behavior of at-risk individuals into account. For instance, although people have been found to have a variety of triggers that can prompt them to evacuate (e.g. feeling earthquake shaking, seeing others evacuating), to the authors’ knowledge these effects have been ignored when conducting an estimation of the numbers of potential casualties. For some coastal areas, during a tsunami large number of visitors could be present, who have less knowledge about the locations of safe places. Nevertheless, there has also been little consideration regarding their presence and behavior. In this study, an advanced approach for estimating the number of tsunami casualties is presented and applied to Yuigahama Beach, Kamakura City, Japan, which has a high risk of tsunami and large number of tourists throughout the whole year.