And it's the serious competitors, like 21-year-old brain cancer honours student Dylan McCuaig-Walton, who have tracked down Sydney's best running routes to prepare for it.

"I think I've done the City2Surf 11 times. It's a great run and a great atmosphere. Every year it comes around, I know a week or two into August what I'll be doing," he said.

"I know everyone talks about Heartbreak Hill but I actually think it's the hills after that that are the most difficult, so you've got to be careful.

"Basically where we live, there is nowhere that's flat, so by default we train on hills."

Mr McCuaig-Walton lives in Oatley, about 45 minutes south of the CBD.

He says that not only do the local tracks offer a secret training weapon for runners – they also offer some of Sydney's best scenery.

"We have some of the steepest hills in Sydney. If you want good training for the City2Surf, it's perfect, because you get views of the Georges River, plus the course," he said.

Mr McCuaig-Walton recommends starting at Oatley Park, then hugging the riverbank before crossing over the Como Railway Bridge.

It's only about an eight-kilometre return trek, compared with the 14-kilometre distance of the Sun-Herald City2Surf, presented by Westpac, but he says there's a detour for those looking to ramp up the intensity of the run.

"You get one of the biggest hills by immediately turning right after the Como Bridge to go under the tunnel beneath the train line," said Mr McCuaig-Walton.

"The top of the hill has a great view of the Georges River."

Southern Sydney is also home to the Cronulla sand dunes, which proved a winning workout session for two-time City2Surf champion Harry Summers, according to his trainer Jim Owens.

Heading up the coast and into Bondi, where City2Surf runners will cross the finish line, the 28-year-old director of Let's Do This, Archie Prescot, says the eastern suburbs offer Sydney's best secret running routes.

"When I was doing my ironman training I used to run from the CBD, all the way through Darlinghurst, up through Double Bay, up Heartbreak Hill and up to Watsons Bay – that's about 10km. Then you can go back to Bondi," he said.

"For my morning runs, I would definitely go to places like Bondi to Coogee, it's awesome."

Mr Prescot says many of the eastern suburbs' hidden City2Surf training gems are places where people wouldn't think to go for long-distance running.

"If you want to do a real quick spin, go to the Royal Sydney Golf Club in Rose Bay. If you do two laps around it, that's about 10km. It's pretty flat so if you want to kind of steam it out, you can do that there," he said.

"It's much the same with Centennial Park. You can fly around that as much as you want or just head in and kind of get lost.

"Turn left and right, don't think about where you're going and just run as long as you can. Then you can just Google Maps where you are and head home from there."

The Manly to Spit Bridge run is another go-to City2Surf training run for Mr Prescot when he heads out to the Northern Beaches.

The North Shore also offers a scenic City2Surf training route starting from Cremorne. Runners can go down to Balmoral Beach, head towards Chowder Bay, then hug the coastline around to Taronga Zoo's south entrance.

If you finish down at Cremorne Point Wharf, 32-year-old hotel manager Dave Pearson says that's about a 15km journey.

"You do get a bit of a beach vibe down at Balmoral while you're running, which is always beautiful and scenic," he said.

"You're also going to run past Gunners Barracks and the Sergeants Mess, which is a really popular wedding venue."

Jacqui Allen, a 30-year-old manager at an airline, lives in Annandale, but frequently uses inner city running routes as part of her training for the City2Surf and beyond.

"City2Surf this year for me is part of my training run as I go into a half-marathon later this year," she said.

"I find that the runs in Sydney that are available, they're made a lot easier to do because the scenery's just so beautiful."

The one she's used most frequently, from Tramsheds opposite Jubilee Oval in Forest Lodge, over to Wentworth Park in Glebe, is only 2km.

But, she says the incorporation of both the oval and Wentworth Park can add on some extra kilometres.

"You've got Jubilee [Oval] at the start of it and Wentworth Park at the end of it. So, if you're doing speed training, you can speed around the oval, run the track, speed around the oval, run the track and so on," she said.

"And, you get views of the Anzac Bridge, the Harbour Bridge and the full city as you're running."

Forty-two-year-old trademark searcher and RunWith coach Bec Rumens, from Burwood in the Inner West, tends to stick more with the local running routes for her City2Surf training.

"I think one of the best runs that I've done training for the City2Surf would be from the Drummoyne end of Iron Cove Bridge, up Victoria Road, over Gladesville Bridge, up through Hunter's Hill and into Lane Cove, which is about 10km," she said.

"It's a real roller coaster in that it's really up and down.

"In the City2Surf you get Heartbreak Hill, sure, but there's a lot of down as well. I think that that's a really great run because it gives you that varied training aspect."

While The Bay Run is one of the more popular running tracks in Sydney, it's also possible to extend the route from 7km up to a 10 or 11km distance.

This can be done by adding in loops of the Bridgewater Park in Rozelle, or the Richard Murden reserve in Haberfield.

The City2Surf will be held on Sunday, August 12. Register online.