Joe Greenwood says the chance to play in the NRL was too good to pass up.
The St Helens forward is headed to the Gold Coast, with Zeb Taia moving the other way.
Greenwood, 23, debuted for Saints in 2012.
“I have been playing at St Helens from the academy level through to the first team for nine years, making it a big decision for me and my family,” he told Sky Sports.
“However, it was an opportunity I couldn’t turn down.
“I’m looking forward to starting my new chapter with Gold Coast Titans. It’s going to be an exciting challenge but can’t wait to get stuck in with the boys.”
Greenwood joins fellow Englishman Dan Sarginson at the Titans.