The 38-year-old has cemented his place in Bilbao folklore, spending 12 seasons in total at the club across three different spells.
Aduriz has also featured for the likes of Real Mallorca, Real Valladolid and Valencia, and has been capped 13 times for the Spanish national team, scoring three goals.
In November 2016, at the age of 35 years and 275 days, Aduriz became Spain’s oldest ever goalscorer when he found the back of the net in a 4-0 win over Macedonia in the qualifiers for the 2018 FIFA World Cup.
Speaking at a news conference on Friday, Aduriz told reporters: "I wanted to communicate that this year is going to be my last year as a professional.
"I will leave football when I finish this season. It makes me especially excited to be able to leave it at Athletic.
"The aim of saying it now is to avoid distractions so I can focus everything on the team. Hopefully we can end the year with something very nice and we can offer all our fans something beautiful.
"I feel very happy to be able to leave football at Athletic. I will compete and enjoy every day until the end. We believe the end never comes, but choosing the end and where I will be at the end is an immense privilege.
"It is a thoughtful decision, which I could've taken last year, but circumstances have made it this year. It is a decision made with my family. I am very proud that I end at Athletic."
Athletic Bilbao begin their league campaign with a home game against champions Barcelona next weekend.
