During her sporting career, Melachroinou trained for Aris Nikaias Swim Club under head coach Antonis Pitidis.

Swimming in heat three, she edged out South Korea's Lee Bo-eun on the final stretch to grab a second seed by 16-hundredths of a second in 1:02.06.

[4][5] Three days later, in the 200 m butterfly, Melachroinou posted a seventh-seeded time of 2:17.60 to hold off a sprint challenge from Singapore's Christel Bouvron by a small fraction of a second in heat two, but finished farther from the semifinal field with a thirty-first-place effort.

[8] On that same year, at the European Short Course Championships in Antwerp, Belgium, Melachroinou, along with Aikaterini Sarakatsani, Nery Mantey Niangkouara, and Zoi Dimoschaki, finished eighth in the 4×50 m freestyle relay with a time of 1:44.88.

[9] Four years later, at the 2005 Mediterranean Games in Almería, Spain, Melachroinou shared bronze medals with Dimoschaki, Eleni Kosti, and Aikaterini Bliamou in the 4 × 100 m freestyle relay with a time of 3:49.70.