Born in Bilbao, Biscay, Basque Country, Jon Iru spent the vast majority of his childhood living in Alicante following the transfer of his father, also a professional footballer, to Elche CF in summer 1993.
[1] After spending some years in Elche's youth setup, he joined Athletic Bilbao in 2010, aged 17, and made his debut as a senior with the farm team in the 2011–12 campaign, in Tercera División.
On 31 August 2012 he was loaned to Segunda División B side Sestao River,[2] but a metatarsus injury shortened his appearances for the club.
[1][3] On 21 June 2013 Jon Iru was promoted to the reserves in Segunda División B, after his loan ended.
[8] Jon Iru made his professional debut on 24 August 2015, starting in a 0–1 home loss against Girona FC.