Speaking to the team's media, Barrett says he's excited to get stuck into work with his new club.
"Looking forward to meeting my teammates and the coaching staff and the management. Once I get to know them, start training with them and playing, I'll get to do other things outside of footy. That's my focus at the moment, be part of my team and getting into my rugby."
"It's awesome to be here, Hannah my wife and Billie are inside, they're so excited. I haven't seen them in five weeks so I'm looking forward to spending a bit of time with them.
The playing opportunities and cultural change aside, Barrett's particularly looking forward to the Japanese cuisine.
"Tonkotsu ramen is number one... basically everything, we love Japanese food."
Barrett is set to return to New Zealand for the 2021 international test season, and will re-join the Blues for Super Rugby in 2022.
The Top League gets underway on January 16 with Barrett's Sungoliath taking on Toyota Verblitz, who are coached by Kiwi Simon Cron and have former All Blacks captain Kieran Read, former Highlander Rob Thompson and Wallabies captain Michael Hooper on the books.