Supercars veteran James Courtney is set for one last lap around the sun and will retire from full-time racing after the 2025 season.

The 2010 Supercars champion announced his decision on Wednesday ahead of the Sydney SuperNight, confirming next year would be his final in the championship.

Courtney, in his first year with Blanchard Racing, has battled to be up the front in recent years.

The 42-year-old last came out on top in 2016, but recently qualified third in Townsville last time out.

"I'll finish this year and do next year then that'll be it for me full-time," Courtney told 9News.

"I've had a hugely successful career, had a great time doing it all and I want to end it on my terms."

Courtney's retirement plans will bring an end to a 20-year career.

The Sydney product debuted at Sandown Racecourse in 2005 with the Holden Racing Team, before moving on to Stone Brothers Racing the following year.

Courtney then jumped to Dick Johnson Racing in 2009, before claiming the championship in a dramatic battle with seven-time series champion Jamie Whincup.

Looking past his days at the racetrack, Courtney sees a future in real estate.

"Real estate is actually my first real job now because racing has been my whole life up until now," Courtney said.

"I'm coming towards the end of the racing side of my life and I saw (real estate) as a natural progression.

"I've always had a massive interest in real estate, whether it's buying and selling my own houses (or for other people)."