We are thrilled that you will be using our service while visiting the USA It sounds like you are looking into purchasing our $40 Simple Prepaid plan that has Unlimited Talk/Text with 3GB 4G LTE correct? If so, this plan will be perfect for you while you are in the USA. If you choose to keep this plan when you go to Costa Rica, you will be able to call and text while in Costa Rica but you will not be able to use data with this specific plan. Calls are going to be $2.69/min incoming and outgoing and text messages will be $0.50 to send and $010 to receive. You will need to have additional funds added to your account in order to call and text while in Costa Rica to cover these per minute/message rates.
Manage your T-Mobile account