To predict the tsunami profiles along coasts precisely and quickly based on the tsunami profiles observed at offshore locations, the present study improved the inversion method by using the epicenter as a priori information. Numerical experimentswere conducted around Nankai Trough. Based on the tsunami profiles observed at 5 offshore locations for 15minutes, the initial water surface distribution and the tsunami profiles along coasts could be predicted with good accuracy.Sensitivity analysis was also conducted to investigate how the number of the offshore observation points and the length ofobservation time affect the accuracy of the prediction. Condition number and Dirichlet spread function were confirmed tobe effective for estimating the accuracy of the prediction even if the true initial water surface distribution was unknown.