Submerged and subaerial coastal morphology, nature and distribution of bottom sediments are among the key factors influencing the environmental impact by tsunami. Here we show our results of the post 2004 tsunami surveys in both offshore and nearshore zones. After the 26 December 2004 Indian Ocean tsunami, new bathymetric map and beach profile measurement along Khao Lak area, SW Thailand were made in 2006. Sedimentological analysis data of 144 bottom sediment samples together with many observation sites by scuba diving and the echosounder profiles were used for creating a detailed map of sediments and rocky bottoms in this area, with a basis scale of 1:30,000. Bottom morphology of the offshore bathymetry, sediment features and distribution patterns in relation to the nature of run-up heights are also discussed. As a result, bottom morphology shows the tsunami impact and run-up reflect the different nature of each contiguous coastal area, and explains how the coastal stretches that were eroded by the tsunami waves were almost fully restored by natural processes of sediment redistribution two years after the catastrophic event.