Rily, Mauritius has a low crime rate, although (as with most places) downtown can get a bit dodgy after dark.Also obviously (because of the number of tourtists) crime is a little higher in Port Louis, Grand Bay, Pereybere, Flic en Flac and Tamarin, but the use of violence is rare. However, an Irish tourist was murdered in her hotel room in the north in January 2011. Most of the problems with dodgy accommodation seems to be from "unregistered" businesses, so make sure you use a legitimate hotel.
other safety issues: there are a lot of sea urchins that wash up on the beach, and broken glass too, so wear wet shoes when you go in the water (it's not so bad at the tourist hotels because they clean the beaches every day). over 7 years ago