It's pay as you go. Walk into the Claro office, and tell them you want a number with them. They'll give you a new sim card. The agent will also be able to scroll through the list of available numbers. If your's is free, you can have it. If not, you can choose any number you wish. I always had a problem remembering my number when I moved here, Claro allowed me to pick my number, and I made it a combination that I won't forget.