Career
Giakoumakis started his career at Atsalenios. In January 2014 he signed for Episkopi on loan until the end of the season and he made a total of 11 appearances and scoring two goals. Greece under-21
On 30 March 2015 head coach Kostas Tsanas announced his first call up (replaced Nikolaos Ioannidis) and make his debut with Greece U21 for an international friendly game at Peristeri Stadium against Croatia U21.