Sun So-eun (also Seon Su-eun, Korean: ? ??; born July 1, 1988) is a South Korean former swimmer, who specialized in freestyle events.
She won a total of two bronze medals, as a member of the South Korean team, in the 4×100 m freestyle (3:44.81) and 4×100 m medley relay (4:13.41) at the 2002 Asian Games in Busan.Sun teamed up with Ryu Yoon-ji, Shim Min-ji, and Kim Hyun-joo in the 4×100 m freestyle relay at the 2004 Summer Olympics in Athens.
Swimming the lead-off leg, Sun recorded a split of 56.86, but the South Koreans missed the final by two seconds outside the top 8, in a time of 3:44.84.