Personal fishing licenses are required for any visitor who plans to fish in Costa Rica. Those who just come along for the ride do not need a license, but anyone who plans to hold a rod must purchase one.
INCOPESCA offers an online way to purchase a fishing license. The form is in Spanish but this article will walk you through the process.

Click this link:
Fill out the fields which, in order, say passport number, first name, last name, email, country, number of days you want the license for, start date of the license.
Click “agregar solicitante” and “aceptar los terminos.”
You will be taken to a second page where you can add the same info for another angler.
You will then fill out the bottom with your credit card info, first name, last name, email, phone number without dashes, leave the two parts that say San Jose, then add your zip code.
Click “procesar solicitud.”
On the next page put in the type of credit card, number, security code, and expiration date.
Click “continuar.”
On the next page, click “descargar” to download a copy of each license.
Print them and keep them with you while fishing.