The Bay to Breakers race was created to raise the city's spirits after the devastating 1906 earthquake. It's a wonderful, wacky tradition, but this year there is a more serious tone.
"I think people want to see police officers in uniform and there will be lots of them," Chief Greg Suhr said.
San Francisco police have been in contact with their counterparts in Boston following the fatal marathon bombings there. And what they've learned means beefed up security on Sunday.
"There will be officers from all the district stations, special ops, tact teams on small motorcycles and horses," Suhr said. "Our own bomb technicians on scene to respond to any packages and also canines around."
And at the start of the race at Main and Howard streets, on the Hayes Street hill and at the finish line along the Great Highway there will be cameras monitoring the race in real time. Officers from other Bay Area agencies and the FBI are all part of the safety plan.
The rules of the race: no alcohol, no floats, no large backpacks, no wheeled objects and no pets.
The alcohol ban has always been hard to enforce and spectators sometimes get out of hand. That's why the Bread and Butter Cafe near the race course will close early on Sunday.
"People started to come in inebriated at 9:30, 10 in the morning by 11, it was people just pretty drunk," James Lener said.
But as the city prepares for the race, organizers and runners like the Famous Sir Francis Drake doorman, Tom Sweeney, are focusing on the fun.
"San Francisco is ready to party all the time, I can't see any problem with that," Sweeney said.