If your cell phone is on the GSM network, you can use it. However, your roaming costs will be high. Your best option is to bring an unlocked phone, and purchase a SIM card here to have a local number–you can obtain one with your passport ID, and activate it at any of the telecommunications companies here, including Claro and Altice. The SIM card costs less than US$5, and you will need to purchase additional phone credit for calls, at your discretion.