Marine Boy is a 2009 South Korean action thriller film. The feature film debut of writer and director Yoon Jong-seok, it stars Kim Kang-woo, Cho Jae-hyun and Park Si-yeon in the lead roles. Marine Boy is the story of a former national swimmer who finds himself in debt, and out of desperation is employed as a mule by a gangster boss, smuggling drugs by sea. Yoon regarded the film's title as a unique point, saying, "There is something beguiling about its duality, how these criminals are called something that romantically calls to mind the popular cartoon Marine Boy or the star swimmer Park Tae-Hwan".

Park Si-yeon is a South Korean actress and beauty pageant titleholder. She joined the Miss Korea 2000 and used that as a springboard to an acting career, she made her acting debut in China in 2004 appeared in minor roles in several CCTV dramas. In 2005 Park was cast in her first starring role in the Korean drama My Girl, though at the time she was more known for dating actor-singer Eric Mun. As she built her filmography in the following years, Park overcame early criticism of her acting skills and eventually gained respect as an actress in TV series such as Bitter Sweet Life, Coffee House and The Innocent Man, as well as the films The Fox Family, A Love, and The Scent.