Thurstans, 29, told the club of his decision today.
Thurstans will be best remembered for his three-goal performance in the 2004 AFL Grand Final.
Recruited from the Dandenong Stingrays with pick 39 in the National AFL Draft at the end of 1998, Thurstans had to wait until 2003 to makes his AFL debut.
Thurstans says his decision to retire had been coming for a while, despite some good form throughout the 2009 season.
“I simply don’t think I have enough left in me to get through another season,” Thurstans said.
“The mental and physical rigours of an AFL season demand so much, and I am not the sort of person who is going to go on unless I think I can contribute 100 percent.
“I’d really like to thank the Port Adelaide footy club for the faith they have shown in me, and especially Choco for the persistence he showed in sticking with me early in my career.
“I’d also like to thank my wife Alana for all her support, and of course my mum and dad who have always been tremendously encouraging.”
Port Adelaide coach Mark Williams says Toby’s career highlights to young players how persistence can pay off.
“Toby retires with an AFL premiership medal after waiting four years to play his first game,” Williams said. “And he didn’t just play in that Grand Final - he played really well.
“Toby has a great football brain, was a wonderful team man with great compassion for others, and has decided to retire on his own terms. We all wish him well for the future.”
Toby retires a Life Member of the Port Adelaide Football Club. He is studying construction management and economics and will now look to develop a career in the construction industry.