Kallinikou represented Cyprus at the 2008 Summer Olympics in Beijing, where she competed for the women's 400 metres. She ran in the seventh and final heat against seven other athletes, including Jamaica's Shericka Williams and Russia's Tatiana Firova. She finished the race in fifth place by four tenths of a second (0.40) ahead of Poland's Monika Bejnar, with a time of 52.40 seconds. Kallinikou, however, failed to advance into the semi-finals, as she placed twenty-sixth overall, and was ranked below three mandatory slots for the next round.