Coastal protection structures such as submerged and detached breakwaters are increasingly being installed to prevent coastal erosion, scouring, and subsidence, which pose serious threats to the stability of these structures. In this study, we used airborne light detction and ranging (LiDAR) bathymetry (ALB) to detect precise topographic changes around artificial underwater structures. Digital surface models with a 1 m grid resolution were obtained for the Won-Pyeong Beach area from ALB data acquired in November 2020 and July 2024. We analyzed the topographical changes (erosion/deposition patterns) and bathymetric contour shifts around pre-existing submerged and newly installed detached breakwaters and groins. ALB has been validated as an effective tool for acquiring precise bathymetric data in shallow waters inaccessible to vessels, with ALB data serving as a foundational baseline for assessing structural conditions, such as scouring and subsidence, and managing coastlines.