Beware of theft
Anyone staying in a mid-range hotel or better will be offered adequate security for their belongings but budget travellers may want to keep a very close eye on valuables. A money belt is recommended not least because many travellers here will have to carry large amounts of cash; although credit and cash cards are a viable alternative given the increasing ATM services available.
Although theft does occur, tourists should not feel unduly concerned in Phnom Penh. If normal precautions are taken and valuables always kept in sight, the city is no more dangerous than anywhere in the US or South America, if not safer.
Walk when you feel unsafe with local vehicle
Perhaps the biggest risk are the roads, which are poorly maintained and vehicles with a distinct lack of safety measures like seatbelts and crash helmets. If you feel queasy on the back of a motorbike, then just walk to avoid the potential for an accident. Take care to dodge stray motorbikes coming from all angles, a common problem here.