It will depend on where you are going. For most touristic destinations and the cities, there are paved roads, but also in ugly conditions and a 4×4 can more comfortable. Even so, a regular is ok. Driving to Caño Negro from the north (Los Chiles) the road is paved. But between Caño Negro and Upala, you will find 25 km of dirt road. But other remote and rural parts of the country do and these are Osa Peninsula, Nicoya Peninsula, and the Costa Ballena