San Francisco is generally a safe place for travelers who observe all normal urban precautions. First, avoid looking like a tourist. Dress inconspicuously, remove badges when leaving convention areas, and know the routes to your destination before you set out. Use common sense and, unless you know exactly where you're going, steer clear of certain neighborhoods late at night, especially if you're walking alone. Below are certain areas to stay on alert, or avoid:
The Tenderloin. Named for a cut of steak, this neighborhood west of Union Square and above Civic Center can be a seedy part of town, with drug dealers, homeless people, hustlers, and X-rated joints. It's roughly bordered by Taylor, Polk, Geary, and Market streets. Avoid coming here after dark, especially if you're walking.
Western Addition. Gang activity makes this a sketchy neighborhood, even in daytime, with occasional outbreaks of gun violence. Don't stray too far off Fillmore Street.
Civic Center. After a show here, walk west to Gough Street; don't head north, east, or south from the Civic Center on foot, and avoid Market Street between 6th and 10th.
Parts of the Mission District. The flat blocks of the Mission range from a bit scruffy to edgy to truly sketchy, with some gang activity. Steer clear of the areas east of Mission Street and south of 24th Street, especially after dark. If you're walking between 16th and 24th streets, head one block west to Valencia, which runs parallel to Mission.
Some areas in Golden Gate Park. These include the area near the Haight Street entrance, where street kids often smoke and deal pot, and around the pedestrian tunnels on the far west end of the park.
Parts of SoMa. Drift a few blocks south of Market and you'll either be near the ballpark, in a high-rise jungle, or exploring the slow transformation of formerly industrial neighborhoods.
Like many large cities, San Francisco has many homeless people. Although most are no threat, some are more aggressive and can persist in their pleas for cash until it feels like harassment. If you feel uncomfortable, don't reach for your wallet.
Distribute your cash, credit cards, IDs, and other valuables between a deep front pocket, an inside jacket or vest pocket, and a hidden money pouch. Don't reach for the money pouch once you're in public.
If you use common sense and follow basic precautions (sticking to well-lighted streets after dark, holding on to your bags rather than leaving them next to you), all should be fine.