Remote sensing technologies play a remarkable role in comprehending the mechanisms and characteristics of the 2004 Boxing Day tsunami. This was accomplished through exploitation of both optical and microwave remote sensing technologies. The main aim of this chapter is to clarify how remote sensing technologies are used to investigate the tsunami and its damage. Therefore, both techniques are mechanically connected to techniques that determine and reckon electromagnetic energy which has interacted with tsunami wave propagation, the atmosphere and materials that are made through tsunami influences. Understanding of electromagnetic (EM) spectrum and EM radiation, of that light, radar, and radio waves are based totally on the photoelectrical theory.