Siam Park's construction started in 2004 and cost 52 million euros (US$58.7 million). Originally stated to open in May 2007, the park endured construction problems and finally opened to the public on September 17, 2008. The park's plans originally included a roller coaster, but the park opted to focus on developing the first phase of the park.

Siam Park includes Thai theming on all of its rides, park buildings, and restaurants. The park's 25 buildings are the largest collection of Thai-themed buildings outside Thailand. The park's designer, Christoph Kiessling, received permission from the Thai royal family to use the park's name and theme; but, to respect the family's wishes, he did not copy royal palaces, temples, or statues of Buddha in the park.[citation needed]