Hawaii is a very safe place to visit. The major dangers in Hawaii come from the natural elements and not other people. Flash floods can be common during heavy rain seasons and box jellyfish and other jellies can be found in waters around the islands. In general, rip currents, reef cuts and other natural dangers are the main things you should watch out for. Learn some basic ocean safety before you go and surf/snorkel with professionals or only when a lifeguard is present if you’re not used to swimming in the open ocean.