England international Billy Vunipola will leave Saracens at the end of the season, the Premiership club announced on Tuesday.
The 31-year-old has spent 11 years at the club since joining from Wasps in 2013, winning five Premiership titles and three European Champions Cup crowns in 194 appearances.
"It's been a honour to represent the people and this great club, through the highs and lows I've enjoyed it all," Vunipola said in a statement issued by the club.
"I will treasure my time here for the rest of my life."
On the international stage, the Australia-born No 8 has represented England 75 times, winning three Six Nations titles, including the Grand Slam in 2016.
He was part of the squad that finished second at the 2019 World Cup and third at the 2023 tournament.
Last week Vunipola received a formal warning from the Rugby Football Union following his alcohol-fuelled arrest in Mallorca in April, but was not sanctioned further by the governing body.
Saracens director of rugby Mark McCall thanked Vunipola for his time at the club.
"To watch Billy develop into a world-class No 8 and a thoughtful, supportive teammate has been a privilege for us all," he said.
"He has contributed enormously to the progress we have made as a club. On the field his intuition and amazing skillset combined with his competitive spirit and physical attributes made him a force to be reckoned with.
"Off the field Billy was sensitive to the needs of the group and a fantastic mentor to many younger players."