The Sentosa Monorail (Chinese: 圣淘沙单轨列车) was a monorail system which served as the main means of transportation on the island of Sentosa in Singapore, which was now currently replaced by the new monorail system, Sentosa Express (For the new 4 station monorail system see Sentosa Express) . The system was constructed at a cost of S$14 million by Von Roll of Switzerland, who also built the Singapore Cable Car
Commencing operations on 23 February 1982, the line had initially only five stations. In 1987, Ferry Terminal Monorail Station began operations when the Sentosa Ferry Terminal opened that year, likewise, in 1991, Underwater World Monorail Station commenced operations when Underwater World opened that year. It operated several 16-car, non-air conditioned trains in a unidirectional counter-clockwise single loop through seven stations located around the western half of the island. The monorail rides were initially charged at S$3 for adults and S$1.50 for children. The trip was later made free for passengers, who could ride the system as often as they wished throughout their stay on the island. Four of the stations have two platforms; for such stations, the Spanish solution was employed, where passengers alight at one platform and board at the opposite platform.
Due to the rapid modernization of Sentosa island, maintenance problems, increasing costs, and declining popularity as visitors started complaining that the ride was slow and uncomfortable, the Sentosa Monorail ceased operations on 16 March 2005 to make way for the new four-station Sentosa Express monorail. Much of the track and all of the rolling stock were sold as scrap for S$350,000. Five of the monorail stations have been repurposed for other uses, such as the "Surrender Chamber" at Fort Siloso, a restaurant being developed at the Central Beach and the SDC Office was rebuilt and now converted into a bar, although Gateway was demolished when the line closed and Ferry Terminal was demolished in March 2007.