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.