The Irish international has spent over five years in Galway
Ulster have announced the signing of Ireland international Rodney Ah You at the end of the season.
The 27-year-old has been based in Ireland since joining Connacht in 2010. He had previously played at underage level for New Zealand.
Ah You has played three times for Ireland. All three caps came in 2014 as a substitute in games against Argentina, South Africa and Georgia.
The prop was delighted with his move from Galway to Belfast. "I'm really excited about the challenges that lie ahead with Ulster. They are a side with big ambitions and are capable of winning silverware in the very near future."
"I feel that the environment at Ulster will allow me to reach my potential and help me to realise my ambitions in the game. With so many players pushing one another for starting places, it will hopefully spur me on to a new level. I feel, at 27, that my best years are ahead of me and I want to push hard for more international recognition too. With the support of my family, I'm looking forward to making Belfast our new home."
"I want to thank Connacht massively for all the support they have given to me and my family over the past five years. It's a fantastic club that is currently competing really strongly in the PRO12 and Europe. I hope they continue to grow and wish them well for the future."
Connacht coach Pat Lam has spoken about his disappointment at losing the prop. "While disappointed not to have him playing as part of the Connacht squad next year, we respect the player's individual decision. I know Rodders wants to do everything he can for the remainder of the season to help the team and his team mates achieve our goals."
The Westerners are at home to Russian side Enisei-STM in Galway on Saturday in the Challenge Cup.