In July 2003, Agrotikos Asteras signed Kostas on a free transfer.
He stayed in the team for five years and he performed in one hundred thirty nine matches, while he scored eight goals.
In July 2008 Kostas moved on a free transfer to Kavala where he stayed for one season but being a team regular as he played in twenty three games and scored two goals.
In summer of 2010 Veria signed Kostas Barbas for three years.
[1] On 21 May 2014, Kostas Barbas left Veria as his contract expired.