The sabbatical was included as part of the contract extension Savea signed with NZR last year and he follows fellow All Blacks stalwarts Beauden Barrett, Brodie Retallick and Samuel Whitelock in negotiating a lucrative spell overseas.
"I'm excited to be joining the Kobe Steelers after the 2023 rugby season," Savea said in a news release.
"Although it's far away, it's nice to have clarity in what I'm doing and I think this change, for a short period of time, will do me and my family good."
Savea, New Zealand's best player so far this test season, will miss the 2024 Super Rugby season for the Wellington Hurricanes.
"We are behind him all the way with this decision, and look forward to seeing him back in 2025," said Hurricanes chief executive Avan Lee.