Keblys qualified for the Lithuanian squad in the men's double sculls at the 2004 Summer Olympics in Athens by finishing fifth in the B-final and eleventh overall from the 2003 World Rowing Championships in Milan, Italy with an entry time of 6:28.380. Teaming with his partner Einaras Šiaudvytis throughout the series, the Lithuanian duo paddled their lifetime best of 6:24.56 for a fifth-place effort in a single repechage round, but failed to advance into the semifinals with only top three boats moving forward. Earlier in the prelims, Keblys and Siaudvytis trailed behind the other three boats in heat three by a wide, nine-second gap with a fourth-place time in 7:07.13.
