Poseidon (Korean: 포세이돈) is a 2011 South Korean action television series starring Choi Siwon, Lee Si-young, Lee Sung-jae, Han Jung-soo, Jung Woon-taek and Kil Yong-woo. It aired on KBS2 from September 19 to November 8, 2011, on Mondays and Tuesdays at 21:55 for 16 episodes.

Choi Si-won, known mononymously as Siwon, is a South Korean singer, songwriter, model, and actor known for his work as a member of South Korean boy group Super Junior. Choi was a special representative for UNICEF Korea from 2015 to 2019, before being chosen as an UNICEF East Asia and Pacific Regional Office ambassador in November 2019.