Getting Here

International airports within Costa Rica:

San Jose, Costa Rica Airport
Juan Santamaria International  (SJO)

Located about 4 1/2 hour drive away from Playa Hermosa.  You can rent a car, schedule a driver, take the public Transportation, or a nice option is a semi-private bus.
Liberia, Costa Rica Airport (LIR)| Daniel Oduber Quiros Airport   
Located about 20 minutes away from Playa Hermosa, this airport caters to airlines like: American, Delta, United, Air Canada and many others.  Please check their website for a full list of air carriers available.  

If flying into Liberia, you can either rent a vehicle, take a short taxi ride, take public bus. 
Public Transportation
There is a bus stop in walking distance.  It is the Playa Hermosa stop on the Playa Panama/Liberia route.  About 45 ride from LIR one bus. 
See bus schedule:
Car rental
A word of warning: 
When renting a vehicle in Costa Rica, there is an insurance policy that is mandatory.  Many companies do not include this in the estimate and travelers are surprised at vehicle pickup.