It is very risky to go out at night in Belize city, dont do it, specially dont walk in the downtown area when the sunlight is gone, it is very dangerous even at 6PM, so many thievesare waiting for the tourist, and specially women should take care, because some men used to drink in the streets and used to touch the women who are passiing thru...Be very very careful at night...
Security is an issue you should bear in mind, particularly with respect to theft. As elsewhere around the world, prudence is needed in carrying money and valuables around, and avoiding certain areas after dark.
If you are staying briefly in Belize before transferring out or onwards, taxis are plentiful. For longer stays, where you plan to visit surrounding destinations, take tours or rent a car.
The international airport is 30 minutes to the north. Unless being met for an onward tour, or to transfer onto a domestic flight, you will need to take a relatively expensive taxi into town. Airport buses exist but are very infrequent and do not coincide with airport arrivals.
I do not recommend getting around by yourself.
Belize city was seemed safe during the day, but It's not very safe at night. Also I would not just wander into any part of town find out what part you don't want to goto and stay out of it.
When i was walking around the streets there was alot of homeless and beggers.