Cambridge has about as much crime as a small city should: not very much. The worst thing a visitor will likely have to worry about is bicycle theft, and this can almost always be averted by using proper locks and bicycle racks. Even though burglaries and violent crimes are relatively rare, the police force in Cambridge is always taking greater steps to reduce crime rates. The police patrol the streets regularly and are  dependable and informed – don’t hesitate to go a police officer with any safety questions you might have. At pub throwing out times on a friday and saturday night, some of the locals can be a little lairy. 

Do watch out for people cycling through the middle of town, though ostensibly a pedestrian zone, cycling is allowed, and some students often don't give the road their full attention!

There are a few other very minor tips that should be kept in mind. The water in the Cam is not safe for drinking or bathing aside form a small area in grantchester (in general, just don't bother!), as in some areas it may be somewhat polluted. Keep an eye on your children playing on the banks, because they may be tempted to drink the water. Also, though it requires an almost unheard of level of clumsiness to fall out of a punt, if it were happen to you, try not to swallow too much water.

Some of the church bells in Cambridge – for example, the Great St. Mary’s church - ring so loudly it is possible to damage your hearing if you are too close. Don’t climb the towers of such churches close to the hour, for the bells could start ringing while you are directly underneath.