The 28-year-old took to social media to unveil the shock switch, swapping his Blues jersey for a different shade with Irish giants Leinster.
"Whats up fam just wanted to announce, I'll be heading to Leinster at the end of the year on a sabbatical break," he captioned on Instagram.
"It's an exciting opportunity to play in Ireland for an iconic team, grow my game and experience something different with my family. Will be back refreshed and ready to rock second half of 2026. Until then locked in with my blues brothers."
The Blues revealed that Ioane has activated the sabbatical clause in his contract, allowing him to seek options abroad.
"120 game Blues veteran Rieko Ioane has taken up the sabbatical clause in his contract and will spend next season at Leinster," read their statement.
"We will have him back in (the right) blue in 2027."
Ioane has been the All Blacks' first-choice outside centre for the last several seasons. By all accounts, he remains committed to New Zealand Rugby for the 2027 Rugby World Cup in Australia.
The talent follows in the footsteps of fellow All Black Jordie Barrett, who blazed a trail at Leinster earlier this year.
Ioane's presence in the Irish capital may ruffle a few local feathers. The centre was public enemy No.1 after reminding Ireland legend Johnny Sexton to not "miss his flight home and enjoy retirement" following the All Blacks epic win over Ireland in the 2023 Rugby World Cup quarterfinal.
Ioane's news comes a day after the surprise move of All Black winger Mark Tele'a to Japan.