The Bureau International des Expositions (BIE), on 26 November 2007, announced that Yeosu will host Expo 2012. It will be a smaller "recognized" exposition lasting just three months. This size expo was also held four years ago in Zaragoza, Spain: Expo 2008. This smaller-sized world's fair allows smaller cities and developing nations to host an event. The larger-sized expos, known as "sanctioned" expos, are held in years ending in "0" and "5."

Yeosu beat out competitors Tangier, Morocco and Wroclaw, Poland. Both Yeosu and Wroclaw had competed originally for Expo 2010, which was awarded to Shanghai, China.

Like most world's fairs, the international participants will have the largest area, in this case a large shared building.

Other notable buildings on site will be the Korean Pavilion, the Theme Pavilion, and the Aquarium.

Off-site an Expo Town has been built to house the workers during the exposition. These buildings will become housing after the exposition.