This paper describes two 3D numerical models to simulate tsunami phenomena including runup onto a complex beach. The governing equations are the continuity and Reynolds equations for incompressible fluids in porous media. In the first model water surface displacement is determined by the vertically integrated equation of continuity, while in the second model by the 3D-VOF method. Topography of seabed can be smoothly expressed with the porous model. These two models were applied to reproduce the existing hydraulic-model experiment, which treated the 1993 Hokkaido Nansei-Oki earthquake tsunami in Okushiri Island. The highest runup calculated by the VOF method indicates the full-scale value of about 30.6m.