The 38-year-old forward has enjoyed a distinguished 20-year career, becoming a Spain international and Athletic favourite across three spells for the club.
Aduriz's star at Athletic has enjoyed a particularly impressive rise since returning to the club in 2012, but he will be 39 by the time the new season concludes and feels it will be time to focus on other facets of life.
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.
🤝 After 12 seasons playing for @AthleticClub ,Aritz Aduriz will retire from professional football.— Athletic Club (@Athletic_en) August 9, 2019
ℹ All the details from the forward´s decision 👉 (link: https://t.co/In9IvwFZ51) #AdurizGutarikoBat #AthleticClub 🔴⚪🦁 pic.twitter.com/kO1RC6n7v0
"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."
Although his first spell with Athletic as a youngster saw him mostly confined to the reserves and out on loan to Burgos in the third tier, Aduriz earned a move to Real Valladolid before returning to San Mames in 2006.
He featured prominently in his second stint with Athletic, but Fernando Llorente began to be preferred in the 2007-08 season, and Aduriz left for a solid two-year spell with Mallorca, scoring 23 LaLiga goals.
That form earned him a move to Valencia and, while his 17-goal haul over two seasons was good given he made only 31 starts, there was little resistance to his departure for Athletic ahead of the 2012-13 campaign.
This time Aduriz was top dog in attack, with Llorente struggling for form as he ran his contract down.
Aduriz's record of 14 strikes in 2012-13 was a personal best at the time, but there was better to come.
The burly striker followed up with 16 the following season, 18 the year after and then 20 in 2015-16, earning him a call-up to the Spain squad for Euro 2016.
Fittingly, Aduriz could feature against all three of his former employers, Valencia, Valladolid and Mallorca, in his final season, following the latter's promotion last term.