In comparison with other western countries, violent crime is relatively uncommon in Spain. In fact, one of the attractions for expats is the sense of safety that many feel when walking around cities such as Barcelona. However petty street crime is rife in the city and precautions should be taken to make sure you don't fall victim to a mugging or bag snatch incident. Common sense behavior such as not carrying large amounts of money or ensuring bags are securely closed are as important here as any other city. Pickpockets work in groups, and are experts in diversion techniques. If someone tries to attract your attention or bumps into you, be especially aware as this could be a purse snatch in action.
One particular scam is to throw a liquid similar to bird droppings on a person. This person is then approached by an apparently well-meaning passer-by offering to help to clean off the offending liquid, and then the victim discovers later that items are missing.
There are also areas of Barcelona that it is wise to avoid after dark, in particular the southern end of Las Ramblas, which although is not dangerous, can be dark and insecure. Other areas of Las Ramblas stay busy throughout the night and are relatively safe, bar the obvious pickpocket menace.
Should you be unfortunate enough to fall victim to a crime, the main emergency number is 112, where you will be directed to the relevant emergency service. To personally visit a police station, you need to report to the local Catalan police service The Mossos d'Esquadra, the police body responsible for dealing with crime within the city and monitoring large public events. There is a police station in Las Ramblas (where more pickpockets occur than anywhere else) which can be found at Calle Nou de la Rambla 76 – 78.
You can also call the relevant emergency service direct using the following numbers:
Mossos d'Esquadra 088
National Police 091
Local Police (for local issues, noise etc) 092
Guardia Civil (for issues outside the urban area) 062
Fire Service 080