IU as O Ae Sun [Young adult]
Park Bo Gum as Yang Gwan Sik [Young adult]
Moon So Ri as O Ae Sun [Middle-age]
Park Hae Joon as Yang Gwan Sik [Middle-age]

Supporting Cast

Kim Tae Yeon as O Ae Sun [Child]
Lee Chun Moo as Yang Gwan Sik [Child]
Kim Yong Rim as Mak Cheon [Gwan Sik’s grandmother]
Na Moon Hee as Chun Ok [Ae Sun’s grandmother]
Yeom Hye Ran as Gwang Rye [Ae Sun’s mother]
Oh Min Ae as Gye Ok [Gwan Sik’s mother]
Choi Dae Hoon as Sang Gil
Jang Hye Jin as Yeong Ran
Cha Mi Kyung as Chung Su [Diver]
Lee Soo Mi as Yang Im [Diver]
Baek Ji Won as Gyeong Ja [Ae Sun’s aunt]
Jung Hae Kyun as Han Mu
Oh Jung Se as Byeong Chul
Uhm Ji Won as Min Ok