Andoni Iraola has informed the Bournemouth hierarchy of his intention to leave the Cherries at the end of the 2025-26 season.
Iraola replaced Gary O'Neil in June 2023 and has gone on to take charge of 121 matches in all competitions for the club, winning 45 of those (D35 L41).
The Spaniard signed a 12-month contract extension in May 2024 to keep him at Bournemouth until the end of this campaign, but he has chosen not to sign another new deal.
In his nearly three-year stint on the south coast, Iraola has led Bournemouth to 12th and ninth finishes in the Premier League, with the Cherries 11th this season.
Bournemouth have six league games of their campaign remaining, with Iraola's final outing coming away to Nottingham Forest on May 24.
Reports have suggested that Iraola informed players of his decision on Tuesday, and the 43-year-old penned an emotional message to the Bournemouth supporters.
"It has been an honour to manage AFC Bournemouth, and I am proud of what we have achieved together," Iraola said in a message on the club's website.
"I'm thankful to the players and staff that I've worked with, as well as Bill [Foley], who have all made my time here so special.
"As for the fans, you have continued to show your fantastic support for myself and the team, and for that I will always be grateful.
"I feel this is the right moment for me to step away, but I will always carry fantastic memories of this club."
Bournemouth's ninth-placed finish saw them break the club record for their most points in a Premier League season, doing so for a second campaign on the spin.
Iraola also masterminded a 2-1 win over title hopefuls Arsenal away from home, extending the Cherries' unbeaten league run to 12 games (W5 D7), their outright longest ever streak in the competition.
It has been reported that Iraola's former club, Athletic Club, are keen to appoint him as Ernesto Valverde's successor, with the former Barcelona boss leaving at the end of the season, though there has been Premier League interest too.
Iraola spent 12 years in Bilbao and played more than 500 games for the club. He was captain of the Marcelo Bielsa side that knocked Sir Alex Ferguson's Manchester United out of the Europa League in 2011-12.