Free karaoke in SF that isn't a one-off tends to build a regular crowd, which means the song queue moves at a real pace and the room knows how to react. This isn't a Wednesday happy hour afterthought — Thursday gives it enough midweek energy that people are actually there to sing, not just watch.

Practical note: street parking in the Tenderloin on a Thursday night is genuinely rough. Take BART or Muni. If you're coming from the Mission, the 14 drops you close. Rideshare pickup on Turk can be slow; walk a block toward Larkin for a cleaner pickup spot.

If you've got two hours: get there early enough to put your name in the queue, order something while you wait, and you'll be on the mic before the night peaks.