In Costa Rica, it is just impossible to survive socially without knowing how to speak Spanish, unless, of course, you decide to keep yourself away from the locals.Demanding the locals to immerse themselves with your culture and learn English is just unfair since you are the one visiting them, right? So it's better that you immerse yourself in their culture and learn their language--Spanish.
Cactus Language offers Spanish courses to teach you that. Classes are held every morning and afternoon at Playa Tamarindo, Costa Rica.
Link: Spanish School in Playa Tamarindo, Costa Rica :: Spanish Courses in Playa Tamarindo, Costa Rica