Women traveling alone in Vietnam face no particular safety issues, and common sense should keep anyone safe. If alone, female travelers in Vietnam (everyone really) are repeatedly grilled about their marital status, and if single, pitied -- a bit exhausting after a while. Some women even revert to wearing wedding bands to end those conversations before they begin. No particular vigilance is required for female travelers, as violent crime is minimal in Vietnam, but the usual precautions about walking alone at night and hitchhiking certainly apply as anywhere. "Cat-calling" happens but is rarely sinister or followed by any action.
Check out the award-winning website Journeywoman (www.journeywoman.com), a "real life" women's travel-information network where you can sign up for a free e-mail newsletter and get advice on everything from etiquette and dress to safety. The travel guide Safety and Security for Women Who Travel by Sheila Swan and Peter Laufer (Travelers' Tales Guides), offering common-sense tips on safe travel, was updated in 2004.