"I just feel it's time," Slater said at a press conference on Tuesday morning. "To be honest, I can't give you a real answer on why exactly (I'm retiring), but I'm 35 this year, this will be my 15th year for Queensland.
"I had a fair indication that the World Cup last year would be the last time I played for Australia, it's been on my mind for a while, I always felt this would be my last Origin series.
"The guys that have gone last year (Thurston and Cronk) and Cam's decision had no bearing for me.
"I just made the decision myself.
"The pressure is relieved letting everyone know and being honest.
"If you asked me as a little boy what I wanted to do it was play for Queensland and Australia and be like (Maroons legend) Allan Langer.
"I was able to fulfil a childhood dream."
Queensland coach Kevin Walters said he was taken aback by the news but praised Slater for his contribution to Queensland over the past 15 years.
"I was a little bit shocked, but I understand he can't keep playing forever," Walters said. "This time last year I was nearly in tears because we didn't have him in the team and now he gets to go out on his terms.
"Billy Slater epitomises what Origin is all about, a kid who makes it from the bush and turns the game upside down.
"He has been phenomenal for Queensland."
The gun No. 1 made his Origin debut as a 20-year-old on the wing in 2004 and has been widely credited with changing the way fullbacks play the game.
He scored a famous try in that series where he latched onto a Darren Lockyer grubber around the halfway mark then chipped over the NSW fullback to complete the amazing passage of play that has gone down in Origin folklore.
"He has changed the way fullbacks play and to have him for 15 years is a dream for all Queenslanders," Walters said.
"Everyone would remember Billy's great Origin try and that makes kids want to be like Billy Slater."
Slater's fearless approach and blinding speed have been hallmarks of a career that has seen him win premierships, Origin series and World Cups.
On an individual front, he was crowned the Dally M Fullback of the Year twice, won the Clive Churchill Medal as man of the match in the 2009 grand final and won the Dally M Medal for the NRL's best player in 2011.
He also won the Golden Boot Award as the world's best player in 2008.
Slater is off contract with the Storm at the end of the year but is yet to make a decision on what his club future holds.
"I'm off contract at the end of the year and I haven't made a decision beyond 2018, but if I do play on, it won't involve representative footy," he said.
"I'm excited about helping the young guys this year.
"It's a huge honour to get to 30 games for Queensland. I've got so many great memories but playing Origin at 20 years old was a huge moment in my life."
