Until recently, fixed observation platforms (e.g., observation buoy, fixed observation station) or manned vessels have been used to monitor water quality and physical characteristics of oceans, rivers, and lakes. With recent advances in autonomous navigation technology, position control technology, and data transmission technology, it is now possible to conduct three-dimensional observations while moving to various points using unmanned surface vessel (USV) platforms in remote areas. Our USV platform can be used to quickly respond to changes in the water environment, such as localized pollution incidents which can’t be detected from a fixed location, and to conduct observations at various points in a short period of time. The USV can collect data at multiple depths for each survey points using a winch, and the collected data is used to derive images showing three-dimensional distribution of the water environment, which helps surveyors to analyze the water environment intuitively. In addition, a side-scan sonar, multi-beam sonar, and LiDAR device can be attached to the hull to conduct underwater and on-water topographic surveys while maintaining a constant speed along pre-planned routes in ocean and river environments.