The properties occupy land leased from the Sa Pathum Palace, which is privately owned by Prince Mahidol Adulyadej's branch of the Royal Family.
The BTS Skytrain, which opened in 1999 with its central interchange Siam Station serving the area, helped cement the neighbourhood's prominence.
It was operated by the Bangkok Intercontinental Hotels Company (BIHC), who would also build the Siam Center shopping centre, which opened in 1973.
BIHC opened its second mall, Siam Discovery, in 1997 amidst that year's financial crisis and construction of the BTS Skytrain.
[3][4] By the 1990s, the neighbourhood, and Siam Square in particular, had become known as the city's main lifestyle destination for urban youth, taking over the role previously held by the Wang Burapha area in the 1950s–1960s.