More than 17,000 runners are registered to tackle Sunday's gruelling 42km course.
The figure is more than double the number who took part in Australia's previous biggest marathon, held in Melbourne in 2019 with 8100 runners.
The event is vying for inclusion as an Abbott World Marathon Major, alongside iconic races in New York, Boston, Chicago, London, Tokyo and Berlin.
Last year, Sydney became the first marathon in the Southern Hemisphere to achieve Platinum Label status, and is now in its second year of a three-year candidacy period to become a major marathon.
Many of Sunday's participants are expected to make for a fast field, including 2022 Men's World Champion Tamirat Tola, 2023 Boston Marathon Men's runner up Gabriel Geay and 2022 Paris Marathon Women's Champion Judith Jeptum Korir.
Tourism Minister John Graham said Sydney had a long history of hosting major international sporting events.
"No city in the world has a greater combination of natural beauty and iconic infrastructure for hosting a marathon than Sydney," he said.
"With so many incredible vantage points and entertainment hubs added to the event, the Sydney Marathon is going to provide a festival atmosphere for spectators and runners."
The event includes five races - a half and full marathon, a wheelchair marathon, a 10km bridge run and a family fun run.
To help raise the marathon's profile, four spectator sites have been set up in Pyrmont, The Rocks, Surry Hills and Moore Park,
The sites will offer free coffee, food trucks, custom sign workshops, DJs, drag queen performances, prize giveaways and large screens broadcasting the marathon live.
The Sydney Harbour Bridge, Cahill Expressway and Western Distributor will all be closed from 4am to 10am Sunday.
The Sydney Harbour Tunnel will remain open but extensive delays are expected.
26°C