The former All Blacks midfielder, who played 30 tests for New Zealand but hasn't featured for the national side since November 2024, is heading to Japan.
Havili has spent more than a decade at Crusaders, playing more than 150 games.
The 31-year-old made his All Blacks debut against the Pumas in October 2017 in Buenos Aires and scored on debut.
He said he is grateful for his time with the Crusaders and All Blacks.
"I definitely feel like it's time for me to move on with the next generation coming through. The legacy is in great hands," Havili said.
"I'm very content. I know that I've done everything I can and I'm very proud of my journey and where I've come from. To be able to live out my dream here for around 15 years and be part of this legacy with some of the best players that have ever come through this club, it's been an extreme honour."
Havili started with the Crusaders in a post-earthquake Christchurch, playing at Apollo Projects Stadium and eventually became captain and led the side in their first game at their new home at Te Kaha Stadium.
He believes the Crusaders are well placed to have a tilt at the Super Rugby title next year.
"The team's in a great spot. With Scott Hansen coming in and strong talent coming through, it's very exciting. There's a lot of mana around that group and I'm looking forward to seeing what they can do."
While the Crusaders were beaten in the semi-finals this season, Havili said he was proud of what the team achieved.
"To go from 10th into 2024 to winning another title and being back where we belong and sending off Apollo with a 32-0 record, that was probably the highlight of my career - leading this team to a title and I'm just so grateful that Penz (coach Rob Penney) gave me that opportunity to be able to do it."
Havili said it's his coaches and teammates that will be the hardest to leave behind.
"It's the people I'll miss the most. The banter, travelling with the boys, those connections. Everyone cares about the jersey and has a common goal."
