St. Petersburg, Florida, held an election for mayor on August 24, 2021. Incumbent Democratic mayor Rick Kriseman is term-limited and cannot seek re-election to a third term in office. Municipal elections in St. Petersburg are officially nonpartisan. All candidates appeared on the same primary ballot, and because no candidate garnered at least 50% of the vote, the top two vote-getters advanced to a runoff election on November 2, 2021. Former Pinellas County commissioner Ken Welch easily defeated city councillor Robert Blackmon in the runoff and became the first black mayor of St. Petersburg.