Elsewhere, promising Western Sydney defender Alex Bonetig has sealed a move to MLS club Portland Timbers.
Tuiloma, 30, returns to play in New Zealand for the first time since joining Olympique Marseille, where he went on to become the first Kiwi to play in Ligue 1 as a teenager in 2013.
The defender has 45 caps for New Zealand and carved out a career in France at Marseille and Strasbourg, then in the MLS with Portland, where he played more than 100 games, and Charlotte.
"I'm ready to play, win games and help the team as much as I can on and off the pitch," Tuiloma said in a statement after joining Wellington on a contract through to the end of the 2027-28 season.
"I know it's been a rollercoaster so far this season, but the Phoenix have the players and the quality and I can't wait to start playing and hopefully help the team go all the way and win a trophy.
"Outside of a handful of games for the All Whites I haven't played in front of my family in New Zealand.
"It's special to be able to come home and be able to play in front of not only a big crowd of Phoenix fans, but my family as well."
The Phoenix (4-2-5) returned to winning ways with a 3-0 away win over Brisbane on Saturday and now sit ninth, but just three points outside the top six.
Wellington will be able to call on Tuiloma from January 14, when the mid-season transfer window opens.
The Wanderers, on a five-game winless run, have landed an undisclosed club record transfer fee for central defender Bonetig, who joins Portland until the end of 2027-28, with a club option for another year.
The 23-year-old joined Western Sydney as a 12-year-old and progressed through the club's academy before becoming a defensive fixture.
"Alex's development over the past few seasons has been outstanding," Wanderers coach Alen Stajcic said in a statement.
"While we'll miss his presence on and off the pitch, opportunities like this are what players work towards.
"The move is thoroughly deserved and we're excited to see him continue his career in Portland."
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