16th and Mission -
The pocket around 16th and Mission is largely because there are many bars, BART, and quite a few homeless people that loiter around that area. It's not particularly violent, but there has been some more violent crimes recently.
South of 24th Street -
If you are wondering south of 24th street, that area can be a bit more dangerous. 24th street itself is safe, but I would avoid walking alone south of it.
24th and Mission -
Again, this area has a cluster a nonviolent crimes because of the BART station and foot traffic that comes through. Though I would say that area is particular dangerous.
Other than that, The Mission is fairly safe, with it's sprinkling of small crimes here and there.