Osiria Theme Park is a key attraction facility in the Osiria Tourism Complex in Busan. We developed the master plan and also designed each facility. Apart from the Lotte World Adventure Busan, the 500,000 m2 site includes Skyline Luge, commercial facilities, and F&Bs. A sports park and hotel where visitors can gather indoors were postponed for secondary development due to the effect of COVID-19. It was quite different from general architectural design as attractions were the main content of the space, and we had to concentrate on various operating mechanisms and uplifting the pleasant feelings of visitors. The capability of Lotte World, the top theme park operator in Korea, and the collaboration with experts, such as Skyline Luge, which became Tongyeong's representative amusement facility, came through. Considering the unique characteristics of theme parks – sensitive to trends – we focused on building a sustainable and adaptable physical environment. In particular, we developed a part of the site, a preserved land, into an ecological forest, constructed an eco-bridge, and maximize outdoor experiences to establish itself as a representative nature-friendly theme park in the Southeastern region.