The Cortes waterfall is in Bagaces, Guanacaste. Catarata Llanos de Cortes is 36 kilometers (22 miles) from Liberia International Airport and about a 35 minute drive.
The Cortes waterfall is open 8AM – 4 PM everyday.
When you pass through the security station, someone will ask you if you want to make a donation to the local community which maintains the waterfall. They told us it was 2000 CRC per person (~$3.34 USD) and she gave us these orange bracelet tag things to leave on the dashboard of our car.