Bulgaria is one of the countries you can visit without much concern. The crime rate here is extremely low, and the safety of Nessebar is an unquestionable fact. The resort area is well-guarded, and attentive (sometimes even overly so) lifeguards on the towers watch over you and your children while swimming.
To ensure your stay in Nessebar is trouble-free, pay attention to two important points:
carefully check currency exchange rates: there may be differences between the rates displayed on street boards and those inside the exchange office;
do not drink tap water. Always buy bottled water and drink around 2–2.5 liters per day, especially in hot weather.