Welsh international Williams scored 21 tries in 29 games during his time at the Halliwell Jones Stadium but was released at the end of the 2013 Super League season.
He has now agreed to join Central Queensland Capras and will head Down Under next week.
“I am looking forward to a new challenge,” said the 24-year-old, who leaves the UK on January 7.
“I went out to Sydney with Warrington for pre-season a couple of years ago and I absolutely loved it. I just want to get out there and enjoy myself and play week in, week out.”
Williams, who comes from the village of Mynydd Isd in Flintshire, started out playing rugby union with Mold before switching codes. He joined Warrington in 2009 and made his senior debut the following year.
Despite an impressive try-scoring record, he found it tough to nail down a regular place with the Wolves and had loan spells with Castleford Tigers, Crusaders and Salford City Reds.
“I had talks with a few clubs but the situation in Super League at the moment means there wasn’t much happening and I am perfectly happy with the decision I have made,” he said.
“Anthony Seibold used to coach with the national team and his brother is with the Capras so that is how it all came about.”
Central Queensland compete in the Intrust Super Cup, one level below the NRL. Winger Williams said his priority was on making an impact for his new club but admits he would love the opportunity to play in the NRL.
“I’m concentrating on doing my best for the Capras and if things happen then things happen,” he said.
As his country’s record try-scorer, Williams plans to remain fully involved with the national team despite playing his club rugby on the other side of the world.
He said: “It was a good experience to be involved in the tournament but it is hard to think about that when you perform the way we did.
“That will stick in my mind for a while and we need to put things right.”
Williams picked up an injury in the tournament and missed the final game against Cook Islands in Neath.