Born in Pamplona, Navarre, Eraso graduated from Athletic Bilbao's youth setup, and started playing as a senior in the 2008–09 season with CD Basconia, in the Tercera División.

[4] He appeared in 42 games during the campaign, as the Madrid club was promoted to Segunda División after a ten-year absence.

[9] Eraso made his official debut for Athletic on 30 July 2015, starting and scoring both goals in a 2–0 win against Inter Baku PIK at the San Mamés Stadium in the third qualifying round of the UEFA Europa League.

[10] He netted his first top-flight goal on 13 February of the following year, equalising an eventual 4–2 away loss to Real Madrid.

[14] On 4 July 2022, Eraso moved abroad for the first time in his career, with the 32-year-old signing a two-year contract with Cypriot First Division newcomers Akritas Chlorakas.