The 23-year-old has decided that Hull is the best place for him, agreeing a two-year contract with the Airlie Birds.
Speaking after signing the deal, Moa said, “This has been one of the hardest decisions of my career, but I know I have made the right one.
“I think Hull are a club on the rise, they have a strong squad with some excellent players and I really wanted to be a part of that.
“They gave me an opportunity and I worked hard this year but now it is down to me to prove to myself I have what it takes to make it at this level and make sure I can be a strong and consistent performer for Hull FC.”
He added, “I play hard and aggressive and I want to bring that to the table next season, this year has helped me mature as a player and now it is time for me to kick on and I know this is the place for me to do that.”