To effectively use the resources of marine environments, it is necessary to consider the deep and remote parts of the ocean. Stationkeeping of floating offshore wind turbines (FOWTs) mainly relies on mooring lines. However, current mooring lines have structural and economical limitations for applications in extreme sea environments. The University of Ulsan is conducting ongoing research to develop a new economical stationkeeping system that can maintain the position of a FOWT in the deep sea using passive flapping foils. This paper describes an experimental study of the stationkeeping of actual structures based on the above-mentioned investigations and suggested directions to supplement the deficiencies in stationkeeping systems using passive flapping foils. This experiment was carried out in the three-dimensional “Widetank” and in actual sea conditions, focusing on the drift of a floater in the surge direction.