Ed Lee died unexpectedly last month and there are a total of 26 potential candidates so far.
On Monday, Mark Leno officially turned in his paperwork. The former state senator, state assemblyman and city supervisor had announced back in May he would run.
He pledges to "shake things up" with a broader approach to the city's problems. "Homelessness and affordability aren't just unique to San Francisco. It's a regional, statewide challenge".
Leno wants to work with regional partners to identify resources.
Acting Mayor London Breed also cites quality of life issues. She's a native San Francisco who was raised in poverty and is personally moved by those on the streets. Breed says as Acting Mayor she's already been working on this issue.
"We've already begun the process of clearing out tent encampments.. providing access to our shelter system, which we've increased, providing access to our navigation centers."
Angela Alioto says it was seeing those tents that propelled her to run. She is the daughter of a Mayor and has run for the seat twice before. She is also a former Supervisor. Alioto says, "The homeless situation is such a crime.."
She worked on former Mayor Gavin Newsom's homelessness plan and says the issue is "a passion of mine."
Supervisor Jane Kim has also pulled papers and expects to formalize her decision to run tomorrow. She cites the lack of affordability as a top issue. She successfully campaigned for free community college.
She ran unsuccessfully for the state senate, but got a boost in name recognition when she was endorsed by Bernie Sanders. Kim says, "My work has been focused on how do we grow and strengthen the middle class and diminish the gap between the haves and have nots."
ABC7 spoke to some of the candidates about their perspectives on the race: