Mark Schwarzer says his decision to quit the Socceroos was a long time in the making, admitting he no longer felt fully committed to his role in the national team.
The veteran goalkeeper called time on his international career on the eve of Ange Postecoglou's first Australian squad announcement as head coach ahead of this month's friendly against Costa Rica.
While his retirement shocked many, including teammate Tim Cahill, Schwarzer insists it was not a rash decision.
"It's been something that I've been playing in my head for quite some time now," he told Fox Sports News on Friday.
"I know for a lot of people it's kind of a surprise that I would've made such a decision - maybe a sudden decision.
"But it definitely hasn't been a sudden decision. You don't go playing for the Socceroos for 20 years and make a sudden decision like that."
The country's most capped player said he had always been 100 per cent committed to the Socceroos but felt that had started to wane.
"I felt that I couldn't give it the commitment that I feel needed to be given to represent your country at a high level and also the World Cup," he said after Chelsea's Champions League win over Schalke.
"Physically I feel really good, but mentally it was the biggest challenge and I just knew it was the right time to move on and pass on the baton as they say and sit back and let someone else take over."
Family also played a big part in his decision, Schwarzer added.
"I'm at a point in my kids' lives and for my wife, I need to be around more to play a part of being a normal dad," he said.
Schwarzer was confident he had left the Socceroos in a "very good shape" but was coy on who he believed should take his spot between the posts.
"There's a lot of good goalkeepers out there. Mitch Langerak played extremely well the last couple of games, we've got Mat Ryan whose playing over in Belgium, Adam Federici at Reading.
"There's a long list and we've always been fortunate enough to have some very good goalkeepers."