Large amplitude internal waves (LAIW, or solitons) are known to change environmental factors affecting coral growth. Previous studies have been shown that LAIW have their greatest impact at greater depth. Therefore, we compared the impact of LAIW and monsoon on coral growth and skeletal density between sites exposed to and sheltered from LAIW and at two depths (7 and 20 m) in the Similan Islands near the Thai continental shelf break (Andaman Sea). Coral skeletons of Porites lutea were sampled at the exposed (west) and sheltered (east) sides of Ko Miang Island at the centre of the Similan Islands. X-radiography and fluorescence analysis were used to examine the linear extension rate due to the annual density banding in the coral skeletons. Measurements of skeletal micro-density, porosity and bulk density were based on the buoyant weighing technique, calculation of the total enclosed volume and measurement of matrix volume by Archimedean methods. We hypothesise that coral growth is reduced at the site exposed to LAIW as compared to the sheltered east. We further assume that coral growth is significantly reduced at 20 m compared to 7 m depth due to the higher impact of LAIW. In addition, the stronger intensity of internal waves and monsoon at the exposed site is expected to cause higher skeletal densities in P. lutea from the respective area.