The application layer of Underwater Lidar segmentation is dominated by four distinct use‑cases: Bathymetric Mapping, Subsea Inspection, Environmental Monitoring, and Defense & Security. Bathymetric Mapping, which involves high‑resolution seabed topography generation for navigation charting and offshore construction, commands the largest share—approximately 40 % of market revenue—because it leverages the longest range capabilities of ToF and FMCW sensors. Subsea Inspection, covering pipeline, cable, and structural integrity assessments, contributes around 30 % of sales; the precision of Phase‑Shift and FMCW units aligns with the stringent tolerance requirements of oil‑&‑gas operators. Environmental Monitoring, encompassing water‑column profiling, habitat mapping, and pollutant detection, accounts for roughly 20 % of the market, driven by growing regulatory pressure and the ability of ToF systems to operate at moderate depths with rapid scan rates. Defense & Security applications—such as mine detection, autonomous underwater vehicle (AUV) navigation, and tactical reconnaissance—represent the remaining 10 %, reflecting higher unit costs but premium pricing for mission‑critical performance. These application segments collectively determine revenue distribution and guide R&D investment across the Underwater Lidar market.