Piutau, an outside back, who has just come back on to the field after missing the first half of the season because of an ankle injury, revealed this week he has signed to play in Japan for the next two years.
The 26-year-old has inked a two-year deal with the Yamaha club, and will be heading north at the end of the Highlanders season.
"Hopefully, I can finish off with the Highlanders and then head up there to play," Piutau said.
"It is family reasons mainly that I'm going up there. I've got another kid on the way, and it is now time for a new chapter in life. I get to learn a different culture, and another way of life."
The Yamaha club is based in the city of Shizuoka, south of Tokyo.
Former All Blacks Jerry Collins and Mose Tuiali'i played for the Yamaha side last year, and Piutau was keen to get into the Japanese scene.
"Goal-wise, top of my list was to play in the World Cup for Tonga and I was lucky enough to be able to do that. That was an awesome experience, something I will never forget.
"Now I have had the bonus of getting another year to play for the Highlanders."
Piutau is just into his second season with the franchise, after he played for the Chiefs for a few games in 2010.
He has not reached his full potential yet but with baby No 4 due on December 24, he said it was time for him to secure a financial future for his family.
Piutau and wife Blossom already have three girls, Emma-Paige (5), Azariyah (3) and Caitlyn (7 months).
"I'm hoping it is going to be a boy but, whatever, it will be a good Christmas present."
Before then Piutau has to concentrate on events on the field, although he admits he is yet to hit top gear.
"I'm still finding my way a bit. The ankle is probably not 100%. I don't feel it during a game but the 24 hours after the game I do feel it a bit. It will still take a couple of months for everything to come back to normal."
Piutai fractured a bone in his right ankle just before Christmas at training and after an operation where ligaments had to be lifted and then screwed back in place, he faced an intensive period of rehabilitation.
"I did not really get a week off training. I had about six weeks on the grinder, working really, really hard.
"After that six week period I was just trying to get back and get some games. It was crucial to play over in South Africa, especially at altitude. That probably helped out a bit with the lungs and that."
But as he gets back to full fitness the Highlanders face a crucial game against the table-topping Bulls side tomorrow.
Piutau, who is likely to be on the right wing, marking big Bulls winger Bjorn Basson, said the key for the Highlanders was just to hold on to the ball.
"We played most of the rugby in the weekend [against the Hurricanes] but just those little errors really hurt us. If we can cut that out and just play the rugby we can do, we'll be right. It just comes down to the individual, and getting the preparation right."