The Tonga-born lock, who can also play in the back row, has won a Super Rugby title with Hurricanes and has also played for the Wellington Lions. Fifita has 11 New Zealand caps, with his most recent appearance coming against South Africa in July 2019.
“I will be working hard to achieve the ambitious goals that the club has set for the future,” Fifita said. “I have confidence that this group can bring pride and success to the people of the region.
“I look forward to meeting you all for the first time at Parc y Scarlets.” Fifita, 29, moved to Wasps from New Zealand for the 2021-22 season.
“We have signed a world-class player in Vaea and this is a real statement of our intent and ambition as a club,” Scarlets head coach Dwayne Peel said.
“Vaea is a superb athlete, an X-factor player with the all-round skill-set that fits with how we are looking to play at the Scarlets. He also brings a lot of experience at international and Super Rugby level and as well as adding Test-match quality to our pool of second rows, that experience will be invaluable to the young forwards that are coming through at the club.
“Vaea is the kind of player that gets fans out of their seats and it’s hugely exciting that he will be pulling on the Scarlets jersey next season.”
