[1][2] Julen Aguinagalde started playing handball in his hometown club Bidasoa Irún.

In 1999 he debuted for the senior team in the top division, Liga ASOBAL.

Here he reached the final of EHF European League in 2007, where they lost to German team HSV Hamburg.

In 2009 he joined league rivals BM Ciudad Real, where he won the Spanish championship in 2010, and the Copa del Rey de Balonmano in 2011 and 2012.

[4] He played for the club for 2 years before retiring in 2022, and joining Bidasoa Irún as a Sporting Director.