Four years after competing in his first Olympics, Advena qualified for his second Ukrainian team, as a 24-year-old, at the 2008 Summer Olympics in Beijing. He finished sixth in the 200 m butterfly from the European Championships in Eindhoven, Netherlands, clearing a FINA A-standard entry time of 1:57.04. On the second day of the Games, Advena challenged seven other swimmers in heat five of the 200 m freestyle, including South Africa's Darian Townsend and Israel's Nimrod Shapira Bar-Or. He cruised to third place by a single tenth margin from Townsend in a Ukrainian record time of 1:48.18, but missed the semifinals by a 0.37-second deficit, as he placed twenty-third overall in the preliminaries. In the 200 m butterfly, Advena posted a time of 1:56.24 to obtain a fourteenth seed on the morning prelims. Then, he repeated his feat from Athens with a fifteenth-place time of 1:56.64 in the semifinals.