The Spanish police have launched their "Tourism and Security - Summer 2009" campaign. To be honest, it's a bit half-hearted (perhaps because they have had considerable success in reducing crime against tourists in recent years), but becoming a crime victim is a sure way to have your holiday ruined, so do pay heed. Crime levels are not high in Spain, on the contrary, but sometimes they can seem so - almost everyone who visits Barcelona in particular either gets robbed or meets soneone else who has been. But don't be paranoid - as the British Foreign Office points out, millions of people have trouble-free visits every year, and common-sense precautions are usually enough.

The brochure being distributed by the Spanish police has this advice to give (I have slightly polished the English):

In general:
- Keep your belongings in sight.
- Protect your handbag or wallet on public transport and in crowded places (street markets, shows, performances, etc.)
- Be careful with your camera / video camera.
- Take only essentials when you go to a beach or swimming pool.
- If you are using a vehicle, do not leave any valuables in sight.
- Avoid isolated or badly lit places as far as possible.
- Beware of suspicious "help" (people telling you you have a stain on your clothes, or something wrong with your car, etc.). This is often a distraction so they can rob you.
- In the street, do not take part in gambling or accept bargains (jewellery, watches...). It will almost always be a trick or a swindle.

In your hotel or flat:
- Do not leave keys, money or valuables around. Use the safe instead.
- In communal areas (reception, restaurants, swimming pools), look after your bags and belongings (handbags, cameras, etc.).

If you are a crime victim, ask for help calling 091 (Police) Or report it on 902 102 112 (several languages spoken)

More:
Crime and Safety in Spain
Welcome to Spain! Enjoy with Security!