The Singapore Indoor Stadium, known exonymously as the Indoor Stadium, is an indoor arena located in Kallang, Singapore. It is within walking distance of the Singapore National Stadium, and collectively form a part of the wider Singapore Sports Hub. It has a maximum total capacity of 15,000 depending on configuration, with an all-seating configuration of 12,000.

One Championship is a multinational combat sports promotion founded on 14 July 2011 by Chatri Sityodtong and Victor Cui. Originally focused on mixed martial arts (MMA), ONE has since expanded to regularly hold events featuring Muay Thai, kickboxing, and submission grappling bouts, while also previously promoting boxing and Lethwei matches. One held its first event on 3 September 2011 at the Singapore Indoor Stadium, and has since held over 200 events across Asia.