Broad, who has played 189 games for Richmond, told his teammates on Tuesday of his plans to bow out.
His departure leaves just six Tigers left at Punt Road from their grand final-winning teams in 2017, 2019 and 2020.
The 33-year-old's final AFL match will be against St Kilda at the MCG next weekend.
Originally from Western Australia, Broad will relocate with his family back to his home state after he finishes up at Richmond.
Already planning to move back to WA, Broad had been weighing up the idea of continuing playing at the Eagles, where former Richmond caretaker coach Andrew McQualter is in charge.
Former Tigers Liam Baker, Tylar Young and Jack Graham are already at West Coast.
Not debuting until he was 23 after being taken by Richmond as a mature-aged recruit, Broad enjoyed immediate success.
In 2020, Broad became the quickest player in VFL/AFL history to win three premierships, achieving the feat in just 70 games.
With Broad exiting, only Nick Vlastuin, Toby Nankervis and Dion Prestia, Jayden Short, Tom Lynch and Noah Balta will be the only premiership players left at Richmond.
Broad hoped the Tigers, who have endured a difficult three years under coach Adem Yze, will recover quickly.
"The culture here is our competitive advantage, but it does not just happen, it has taken years to build," he told teammates.
"It can also be lost in a matter of moments.
"Continue to water and feed this culture, because it is our biggest strength."
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