Pickpocketing is the most pressing issue for visitors to Barcelona. Never keep your wallet, cash or important documents in trouser pockets or in bag pockets: a money belt is an easy and inexpensive way to prevent being robbed. As always, be alert in crowded places, such as public transport, train and bus stations, La Rambla and Raval. If you are in a crowd, beware of anyone suspiciously or with no intention deliberately coming close to you.

Pickpockets usually work with more than one people, with one person using all kinds of tricks to distract you as their accomplices take action. The following are a few common methods:

People in Barcelona are often very friendly and love to practice their English, so don't be unfriendly. That said, you should, of course, be suspicious if someone approaches you in a touristy area speaking your language and asking you for help. This should put your guard up immediately. Do not be tempted to sign their petition, give them directions, or help them with their problem. You don't know anything about where you are, since you're a tourist, so you won't be able to help them in any case.

Professional scam artists exhibiting a high degree of coordination are active in many areas of the city. Be careful in tourist areas. A variety of methods are employed, including the No-change trick. A common scam involves fake cops who will show up ask to see your passport, then take your belongings at the first opportunity. The story varies, but they are almost certainly not real ones. When it happens, the best strategy is to just walk away instead of starting any sort of conversations with them. Another trick is that one seemingly confused person will ask you for directions, diverting your attention and then suddenly fake police will appear asking for your ID. This is a co-ordinated move to divert the attention and steal whatever is possible. If such incident happens, just walk away, without listening to any of their conversation. Stay alert, especially in busy tourist area near the Sants station and Plaça d'Espanya.

Another popular scam happens in the metro. A group of scammers (often middle-aged women) will take advantage of the fuss while people are entering the metro and surround a tourist, frantically asking for directions. Most tourists won't know what to say while one of the scammers empties their pockets. They will try to confuse the tourist while the metro stays in the platform, and will get out just before the doors are closed. When you realize you've been scammed, the train will have already left and they will be safely outside with your belongings.

The bird excrement scam is also common. One or more accomplices will secretly spray or throw a smelly liquid on you. When you look up thinking a passing bird has pooped on you, they will run up to you and tell you that they saw a bird poop on you. They will offer to help you clean up, and while you are cleaning they will go through your pockets and any bags you have set down. It is wise to beware of anyone who is attempting to touch a complete stranger.

A version of Three Card Monte is one of many common scams played on Les Rambles. There are also people holding petitions to install a wheelchair lift in locations with a lot of stairs. Once your signature is obtained they will then aggressively ask for a donation. Sometimes there can be crowds of children demanding money with hardly anyone else in the area, making it difficult to get away.

In 2019 there was a surge in violent crimes around Barcelona: in just the summer, there were almost as many violent deaths as there were for the whole previous year. While tourists are very rarely targeted, so for the regular tourist this should be not a concern, many of these deaths are either drug-related or take place during drunken fights, so you are best advised to avoid such situations.

Local club FC Barcelona (also known as "Barça", a term used by locals to refer strictly to the club and not the city) is seen as a symbol of Catalan nationalism, and has a very heated and politically-charged rivalry with Real Madrid, which is seen as a symbol of the Spanish state and ruling establishment, and violent confrontations between the supporters of both clubs have been known to occur. Avoid wearing Real Madrid jerseys while you're in Barcelona, especially on matchdays, as that could result in you being singled out for violence by local fans.

On the other hand, wearing an Atlético Madrid (the other Madrid club) jersey might get you some stares and a couple of harmless teasings, but certainly no violent reactions.

Barcelona offers ATMs in many locations. Many provide a wide range of services (withdrawals, transfers, mobile credit recharges, ticketing, etc.), and most accept ATM/debit/credit cards of various banks. Choose an ATM in a secure or highly-public space (e.g., in a bank lobby or airport terminal) to avoid machines modified by criminals to skim/video your card data or where you might be robbed after use. Ensure early in usage that the ATM supports a language you understand. For a full discussion of safe/effective charge/debit/ATM card usage and their cost trade-offs, see Money.

Be very careful in the Barcelona Sants train station where thieves prey on new arrivals, even on the platforms. In general, try to stay away from suburban trains (cercanias in Spanish or rodalies in Catalan) late in the evening, as you may encounter young offensive drop-outs that disturb passengers, smoke, break windows and vandalize equipment. Don't rely too much on the railway security staff, as they prefer not to get involved, and by all means avoid messing with those troublemakers.

Women travelling alone should exercise caution while exploring the more isolated parts of Montjuïc. The city beaches, particularly the ones adjoining Barceloneta, have proven to be quite lucrative for bag snatchers. Anything that you would rather not lose is best left, locked, in your hostel or hotel.

Men traveling alone should expect the prostitutes on Les Rambles, St. Antoni, and Raval in the early hours to be very aggressive and in league with pickpockets and robbers.

Also, people need to be careful when leaving the bars of the Olympic Port late as there are many pickpockets around.

Women should be wary of wearing exposed jewelry such as gold chains and necklaces. People walking down a street may be attacked from behind by a thief who may grab the necklace and try to rip it off the woman's neck before quickly running away, often down a convenient side street. Be especially careful of seedy looking men on bicycles, as grab and snatch assaults can occur.

In the event of such a robbery, people will need to find the local police station to report the incident, especially if a travel insurance claim is going to be made. Don't expect any police action beyond the report, though, as these types of events are par for the course and arrests, even when made, almost never lead to prosecution due to a slow, antiquated, and overburdened legal system.

Parts of Barcelona are covered by closed circuit TV surveillance, but only the more popular spots.

Many Barcelona residents have the impression that there are too many tourists in Barcelona and that it has increased living costs, as landlords prefer to rent to tourists and not to locals to make more profit. Also, a lot of local shops have closed to make way for souvenir spots, so many locals feel they are being expelled from areas they have lived their whole life. In some areas, particularly the ones next to the beach where drunken tourists often stroll in swimming suits, there were anti-tourism demonstrations by locals, which had the backing of the Mayor of Barcelona. By October 2019, this movement had nearly disappeared from scene.

Tourist drivers may attract special attention, such as Red light bag snatch or Flat tire scams

Besides being a particular pickpocket hot spot, there are plenty of fare evaders who will stick to you when crossing a fare barrier. Do not even attempt to block their way and let them pass, as many of them can be quite aggressive. Although stations are full of surveillance cameras, they are seldom used to either enforce fare payment or as a proof for filed assault charges, except in the most severe cases. Lack of staff in many stations and few ticket inspections effectively mean carte blanche for them. The fare evasion fine is just €50 if paid on spot, no matter how many times the culprit has previously been caught, and many fines remain unpaid because payment enforcement is legally way too cumbersome.

If you need to report a crime (for example, to claim on travel insurance), be prepared for the reality that in the downtown police station, officers generally do not speak English, even though the theft report form is in English, Spanish, and Catalan. The police station most often used to report theft is the one underneath Plaça Catalunya beside metro station, where they have some translators for common world languages.