Korsis Island (Bulgarian: остров Корсис, romanized: ostrov Korsis, IPA: [ˈɔstrof ˈkɔrsis]) is the rocky island lying 150 m off the northwest coast of Snow Island in the South Shetland Islands, Antarctica. It extends 300 m in southeast-northwest direction and 180 m wide. The feature is named after the Bulgarian military commander Korsis, 9th century.
Korsis Island is located at 62°44′49.5″S 61°29′44″W / 62.747083°S 61.49556°W, which is 1750 m northeast of Byewater Point, 760 m east-northeast of Gergini Reef and 2.93 km southwest of Bizone Rock. Bulgarian mapping in 2009.