Sentosa is a 500-hectare island resort in Singapore. It has a number of themed attractions, spa retreats, rain forests and beaches, resort accommodations, golf courses, and is home to Universal Studios Singapore.
The island can be reached by various forms of public transportation, of which Sentosa Express monorail is the most common. The monorail is fully wheelchair accessible. There is a cable car on the island that is somewhat accessible. The staff can slow down the carriages to 1m/s but not fully stop them, so a wheelchair user has to back into a moving carriage that is just wide enough to fit the wheelchair (but not turn around)! While it can be done, it may be nerve-wracking.
In general, the island is fairly accessible but some routes (like from Sentosa Merlion to Madame Tussauds) are not straight forward as the island has some steep hills in the middle. There are many accessible toilets available.
Many, but not all, attractions are accessible. Since the attractions are run by different operators, it is best to check accessibility with the operator directly.