Coastal regions of the world are increasingly threatened by the effects of global climate changes. One of the most prevalent among them is sea level rise (SLR). In order to quantify the effects of SLR, it is essential to have accurate high-resolution elevation data. Although several analysis techniques have been used to help provide some of the data necessary to undertake such studies, there is a demand for the development and application of a more sophisticated technology. This chapter discusses techniques and applications of light detection and ranging (LiDAR) technology in coastal ecosystems. In particular, procedures are described for processing airborne LiDAR data collected over coastal regions, developing Digital Elevation Models (DEMs) and Digital Terrain Models (DTMs), and validation of LiDAR outputs with in situ data. Marine applications of bare earth DTMs are also illustrated.