Career
Kosti trained throughout her swimming career for Olympiakos sports league in Athens under the tutelage of her coach Markos Mantaloufas. She swam the anchor leg on the outside lane in heat two, but her team was disqualified due to an early relay takeoff by Matsa. In 2005, Kosti helped her Greek teammates Dimoschaki and 2000 Olympians Aikaterini Bliamou and Zampia Melachroinou atone from their Olympic disqualification in Athens to relish for a bronze-medal victory with a 400-metre freestyle relay final time of 3:49.70 at the Mediterranean Games in Almería, Spain.
On her second Olympics in Beijing 2008, Kosti swam the individual freestyle double with only two days in between.
On the third night of the competition, she closed out the field to last place and forty-fourth overall in heat three of the 200 m freestyle, finishing with a time of 2:04.55. Two days later, in the 100 m freestyle, Kosti escaped from the bottom of the field to finish heat three in seventh position and thirty-seventh overall with a time of 56.44, edging out Slovenia"s Nina Sovinek by almost a full second.