Some travelers have had difficulties traveling in and around Costa Rica.

You may want to be extra careful in certain situations. Make sure to secure your belongings, specially your passport (losing this will certainly ruin any vacation). Some examples are:

Car:

If you leave the car to investigate damage to it, or go to eat or enjoy a view. Also don't travel with your purse or laptop in plain view in San Jose. 

Beach:

If you leave them unattended on the shore while you swim. If you need to swim, take the time to leave your wallet or valuables at the hotel safe. 

Hotel:

If they are openly visible at the hotel. Perhaps use the hotel safe.

The bottom line is to consider your destination, take only those things that are essential, and secure them as thoughtfully as you can. There are lockers at the airport, hotel safes, and if you have great pictures on your camera - upload them an online site or email them to yourself - a camera is easy to replace, but priceless photos aren't. Don't let a petty theft ruin your vacation.