Early identification of the most critical slip surface location in landslide investigations is crucial for subsequent mitigation efforts. Typically, geometry of landslide slip surface are estimated through interpretation of borings or boreholes information, which may require extended periods of observation in some cases. Several methods have been proposed to quickly assess the geometry of the slip surface using surface displacement vectors in landslide areas. However, various supplementary methods have been necessary to compensate for the decreased accuracy resulting from the limited number of measurement points. In this study, high-precision topographic data were obtained using laser-equipped UAVs at two landslide sites. High-density ground surface displacement vectors were computed from these data and slip surface geometries were estimated based on this information. The comparison with the slip surface geometry determined by survey boring confirmed that the estimated slip surface geometry is sufficiently accurate for planning future landslide mitigation strategies.