This year's Sundown Marathon has been moved to the heart of town, with its race routes revamped to include part of the Singapore F1 Grand Prix route.

Flagging off at the F1 Pit Building, runners from all three categories (full marathon, half marathon, 10km) will go past some of Singapore's most iconic attractions, including Marina Bay Sands, Gardens by the Bay and the Singapore Flyer.

Said Adrian Mok, director of race organisers HiVelocity Events: "Thanks to the F1 night race, Singapore has become known globally for its magnificent cityscape at night.

"With the Sundown Marathon heading into its sixth edition this year, we wanted runners to experience this amazing urban landscape to motivate them as they run and perhaps get a glimpse of what it's like to run on part of the F1 route."

The ultra-marathon (100km) is making a return this year and will be held on Sept 14.

Early bird registration for the May 31- June 1 event has closed but participants can still enjoy discounts before the special period window closes on Thursday.