3G will work but what Lovecraft was saying is that it may not be available on pay as you go sim cards. I have no idea whether it is only available on contract only numbers as the 3G coverage seems to be available in the capital rather than out here in the sticks. If it is allowed on sim card only numbers the cost I imagine will be expensive.
If you can read Spanish take a look at some of the mobile company websites like Movistar,Claro and Personal networks for more info.