IF YOU ARE VISITING COSTA RICA, YOU NEED TO KNOW:
If you are visiting Costa Rica for the first time, you should know that citizens of the United States, Canada, and most Latin American and European countries are entitled to stay in Costa Rica for 90 days. A tourist visa is issued at customs. However, they enter the country with a departure ticket and a valid passport that does not expire within 30 days of their arrival to Costa Rica.
Yes, you do need a visa to be in Costa Rica. You cannot legally live here without applying for legal resident status.
What happens after the 90 days is up?
You have to leave Costa Rica to get your passport stamped renewed. Border runs to Nicaragua or Panama (perpetual tourism), are frowned upon by immigration.
If you are overstaying in Costa Rica you will be subject to fines because as of August 1, 2014, Costa Rica is implementing new laws for those who overstay their visa. Foreigners overstaying their visa will have to pay a fine of $100 for each month they remain in the country after the expiration of their visa. In addition, they can be barred from re-entering Costa Rica for a period of 3 times the length of the time they overstayed.