Born in Elgoibar, Gipuzkoa, Etxeberria began his career
with Real Sociedad,
making his top level debuts at only
17, in a 2–0 home win against RCD Español, on January 29, 1995. That summer, he
moved to neighbour Basque outfit Athletic Bilbao, in a
controversial transfer that cost over €3
million. At the time, it was the highest transfer fee paid for an under-18
player in Spanish football.
In 1997–98, Etxeberria netted 11 league
goals, as Athletic finished second, achieving a career-best 14 five seasons
later, while he was also eventually awarded club captaincy.
On 1 October 2008, already playing second-fiddle for the team, Etxeberria
agreed a deal with the club according to which he effectively played 2009–10, his
last season as a professional, for free, after his contract expired in June
2009.
Etxeberria's last season was not a successful one individually, as he only
appeared in seven league matches (plus another seven – with two goals – in the
UEFA Europa League). On May
15, 2010, he was replaced to a standing ovation in Athletic's 2–0 home win
against Deportivo de La Coruña, and
represented his main club in 514 official matches (105 goals), third-best in the
team's history, only behind José Ángel Iribar and Txetxu
Rojo.