In a city reknowned for petty theft, it's worth while taking a few precautions.

The first is that the main thoroughfares are home to some skilled and professional pick pockets. These people will be invariably well dressed, and look like business people or tourists. They pick easy targets, people who have had a bit to drink or people who are distracted by what's going on around them. Don't carry your passport around with you. Keep your valuables secure; if you're male then the front pocket of your pants is a whole lot harder to get into than an inside jacket pocket; if you're female ALWAYS wear your handbag facing front, that is, keep it against your chest and never slung over your shoulder behind you.

Watch out for scams. Three card monty is the oldest con in the book, whether it's played with 3 cards or with 3 cups and a pea. Nobody ever wins. Nobody. Ever. When you see someone winning you are looking at one of the conman's friends. He'll have several, and every now and again one will win a lot of money, this convinces the mark that the game is one that can be won. It can't. The winner will walk off, but within 30 minutes he'll be back to win again. Even stopping to watch the game makes you a mark, because you'll find yourself in a small compressed bunch of people, and it's easy to pick-pocket anyone when others are pressed against them. If you stop, make sure that you have empty space all around you and keep an eye out for people trying to move closer.

The main danger areas are Las Ramblas, the walkways leading to the beach and all along the beach, the beach itself, Plaza Espana, Plaza Reial, and Plaza Catalunya.
Beware of youths riding scooters! One of the most common methods of theft is the use of the scooter, and you should be especially wary where you see a passenger on the back. They fly past and whip bags from shoulders, which can often lead to the victim being injured if they are dragged to the ground. However, this can only happen if you're not looking at them, so if you hear a bike behind you, always turn to see what's up.

Finally, use your common sense. There are areas of the city that are obviously dodgy late at night, if you're walking alone stick to the main thoroughfares and avoid the many poorly lit, narrow back streets. If you've had too much to drink, take a cab - they're quite cheap. Always keep a sheet of paper with the address of your apartment on it, and just hand this to the driver when you get in. But beware, don't loiter outside the cab, and be careful of your bag as you climb in as you are particularly vulnerable at that moment.

So. The trick to a crime free holiday is using common sense. Enjoy your stay!!