We report on the integration of subaerial and subaqueous surveys, on the basis of, respectively, SPOT satellite images and data acquired from a combined side-scan and profiler sonar system, of a barrier island on the west-central coast of Taiwan. Our results establish a case study of a natural barrier island (i) the morphology and position of which have been dramatically affected by human alteration of a sediment-supplying river during the 200-year interval 1790–1990, but (ii) whose partial destruction and migration have been mitigated significantly in recent years by a combination of tectonic and climatic events. These events have been shown elsewhere to have increased riverborne supply of sediment to the Taiwan coast, and we propose that this development, in turn, contributed to the observed stabilization of the barrier island in size and location.