If you're coming to Panama for a visit, it's cheaper to buy a disposable phone in Panama and put $10-$20 of credit on the phone than to use your foreign-based service.
If you run out of credit, no need to hunt down a cell phone office. Just go to your nearest grocery store, mini mart or Chino and you can buy cell phone credit and then input the credit on your phone via a simple code. (By the way, a Chino is a local's mini mart that typically has a person's name attached to it, like Jonathan or Melissa or Isabella. These are often owned by Panamanians with Chinese heritage and are therefore called Chinos. It's not a derogatory term but rather a term the Panamanians use to describe something, similar to calling a blonde woman "a blonde.")
The main cell phone providers in Panama are Claro, Digicel and Movistar. Expats who move here typically invest in a nicer phone as their main phone, but keep a disposable phone from a different provider as a backup to make sure cell phone service is always available.
To get a phone, you simply need to provide a copy of your passport and choose a prepayment amount. You will get a phone and a phone number. Nothing could be easier. Just charge the phone and you'll be ready to chat away.
One of the services offered by Panama Relocation Concierge is to provide clients with a complimentary cell phone while you are visiting Panama and looking at property.