The 25-year-old has joined Trinity on a two-and-a-half year deal, keeping him at the club until the end of the 2021 campaign.
The forward can be utilised in the middle or back-row and joins Wakefield with immediate effect.
He is in contention to play at Anfield this weekend, as Wakefield prepare to face Catalans Dragons at Magic Weekend on Saturday (2pm).
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“I’m really excited to be joining Wakefield," said Tanginoa, who started his career at NRL side Parramatta Eels.
The Australian forward joined North Queensland Cowboys in 2015 before returning to Parramatta in 2016.
Last season he made 12 appearances for Manly Sea Eagles and is "keen" to get going at Wakefield.
He added: “There are a few boys that I know already such as Tinirau Arona, Jacob Miller and David Fifita.
"I met the rest of the boys this morning (Tuesday) and they seem a really good bunch. I’m looking forward to us all working together.
“I’m just trying to stay ready. Hopefully I get the opportunity to play alongside the boys and if I get the chance I won’t hold back. I’m feeling pretty keen."
Head coach Chris Chester admits that the forward has been on his radar for a number of years.
The signing follows the news of Justin Horo's departure from Belle Vue and Chester feels Tanginoa's arrival will give his forward pack a "big boost."
“I’m over the moon we’ve got Kelepi tied down for the next two and a half years," said Chester.
"He’s a player I’ve been trying to sign for the last few years, so to have him on board now is great for us.
“At this stage of the season, he will give the pack a big boost and help us go forward.
"He’s straight into training this morning and looking sharp, so I’m looking forward to seeing him out there on the field.”
Wakefield are also continuing their retention for next season, with four out contract players offered new deals this week.