The race, which is now in its 103rd year starts near the Embarcadero and ends at Ocean Beach.
Officials say there are a few changes that focus on safety this year. Crews installed fences around Alamo Square Park to keep runners and revelers out.
For many runners, Bay to Breakers is less about the finish line and more about having a good time.
However, at the race expo on Friday, ABC7 News found dedicated runners like Rebecca Daniels.
"Last year, the hill was a little intense and this year, got it," Daniels said.
For her, prep involved extra workouts. For others, it involves costume shopping.
For the city, race day prep requires much more. Security is a major focus of this year's event with additional officers coming in from Sacramento and San Jose, along with a 20-percent increase in private security.
Alcohol is once again officially banned.
"If we do see alcohol we will take enforcement action as those violations occur," San Francisco Police Department Ofc. Albie Esparza said.
Last year, two men died in connection to the iconic San Francisco celebration, a tragedy race organizers want to avoid.
"Obviously we want people to have fun, but we want people to be safe. This race has a ton of history, it's been going on consecutively since 1912, so we want to honor that history and that tradition, but we want it to be a very safe environment," Bay to Breakers organizer Matt Wikstrom said.
About 40,000 registered runners and 100,000 fans are expected to line the streets of San Francisco Sunday.
If you plan to come into San Francisco for the race, BART will be running earlier than usual on Sunday and they'll have extra cars. And the Larkspur ferry will make four early morning trips to the San Francisco ferry terminal, which is just a few blocks from the start.